Our official Japanese journal "Naibunpigaku Zasshi" was first issued in 1925 and renamed as "Nihon Naibunpigaku-kai Zasshi" in 1927. In 1954 the first issue of English official journal "Endocrinologia Japonica" was published continuing to Volume 39 in 1992 and then renamed as the present "Endocrine Journal" from Volume 40 in 1993.
Teikyo University, Tokyo
Gunma University, Gunma
Kyushu University, Fukuoka
Nagasaki University, Nagasaki
International University of Health and Welfare Hospital, Tochigi
Hamamatsu University School of Medicine, Shizuoka
National Graduate Institute for Policy Studies, Tokyo
Jae Hoon Chung
Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
Tokyo Medical and Dental University, Tokyo
Kuma Hospital, Hyogo
National Hospital Organization, Kyoto Medical Center, Kyoto
Gunma University, Gunma
Parathyroid, Vitamin D, Bone
Teikyo University, Chiba
Osaka Women's and Children's Hospital, Osaka
Gunma University, Gunma
General Women's Medical and Health Science Center, Rakuwakai Otowa Hospital, Kyoto
Juntendo University, Chiba
St. Marianna University School of Medicine, Kanagawa
Keio University, Tokyo
Fukuoka University, Fukuoka
Keio University, Tokyo
Osaka University, Osaka
Diabetes, Lipid, Obesity
Iwate University, Iwate
Gunma University, Gunma
Shinshu University, Nagano
University of the Ryukyus, Okinawa
Miyazaki University, Miyazaki
Saitama Medical University
Tokyo Shinjuku Medical Center, Tokyo
Osaka University, Osaka
Teikyo University, Tokyo
Kyoto University, Kyoto
National Center for Global Health and Medicine, Tokyo
Catholic University of Korea, Seoul, Korea
Gunma University, Gunma
Tohoku University, Miyagi
Awarded to the first author and/or the corresponding author (both must be members) of an article with the highest citation index
The affiliations are those when awarded.
Hotaka Yamada (Jichi Medical University)
San-e Ishikawa (International University of Health and Welfare)
There is evidence that betatrophin, a hormone derived from adipose tissue and liver, affects the proliferation of pancreatic beta cells in mice. The aim of this study was to examine circulating betatrophin concentrations in Japanese healthy controls and patients with type 1 and type 2 diabetes. A total of 76 subjects (12 healthy controls, 34 type 1 diabetes, 30 type 2 diabetes) were enrolled in the study. Circulating betatrophin was measured with an ELISA kit and clinical parameters related to betatrophin were analyzed statistically. Circulating betatrophin (Log transformed) was significantly increased in patients with diabetes compared with healthy subjects (healthy controls, 2.29 ± 0.51; type 1 diabetes, 2.94 ± 0.44; type 2 diabetes, 3.17 ± 0.18; p<0.001, 4.1 to 5.4 times in pg/mL order). Age, HbA1c, fasting plasma glucose and Log triglyceride were strongly associated with Log betatrophin in all subjects (n=76) in correlation analysis. In type 1 diabetes, there was a correlation between Log betatrophin and Log CPR. These results provide the first evidence that circulating betatrophin is significantly elevated in Japanese patients with diabetes. The findings of this pilot study also suggest a possibility of association between the level of betatrophin and the levels of glucose and triglycerides.
Kohei Okita (Hyogo Prefectural Nishinomiya Hospital)
Homeostasis model assessment of insulin resistance (HOMA-IR) is a simple and useful method for evaluating insulin sensitivity. But it is difficult to apply to type2 diabetes patients treated with insulin. We have devised a method for measuring HOMA-IR and investigated the validity of HOMA-IR for evaluating insulin sensitivity in patients with type 2 diabetes on insulin therapy. In the first arm of the study, 19 poorly controlled diabetic subjects were treated with insulin and underwent euglycemic clamp study. Then the relationship between insulin resistance index assessed by the clamp test (clamp-IR) and HOMA-IR was investigated in these subjects. Log transformed HOMA-IR correlated with log transformed M/I values derived from the standard euglycemic clamp (r=-0.753, p=0.002). In the second arm of the study, we investigated the relationship between HOMA-IR and various clinical parameters in 156 patients with poorly controlled diabetes after glycemic control. Log transformed HOMA-IR correlated negatively with age (r=-0.292, p=0.0002), HDL-C (r=-0.342, pρ<0.0001), log transformed serum adiponectin (r=-0.309, p=0.0006) and log transformed KITT (r=-0.264, p=0.0009), and positively with body mass index (r=0.499, pρ<0.0001), waist circumstance (r=0.461, pρ<0.0001), visceral fat area (r=0.401, pρ<0.0001), diastolic blood pressure (r=0.223, p=0.0054), log transformed triglyceride (r=0.497, pρ<0.0001), urinary CPR (r=0.216, p=0.0099), ΔCPR of glucagon stimulation test (r=0.496, pρ<0.0001) and log transformed insulinogenic index (r=0.325, p=0.0002). These results suggest that HOMA-IR is a useful test for the evaluation of insulin sensitivity even in patients with type 2 diabetes treated with insulin.
Yuji Hiramatsu (Okayama University)
Glycemic control is an important issue in gestational diabetes mellitus (GDM) and in diabetic pregnant women. We determined the reference intervals of glycated albumin (GA) and hemoglobin A1c (HbA1c) as glycemic control markers in healthy Japanese pregnant women and analyzed their time courses and factors that influence these variables during pregnancy. 676 women were screened for the present study. After the exclusion of non-pregnant and puerperal women, 574 women were studied to determine the reference intervals. HbA1c, GA, casual plasma glucose, urinary glucose, urinary protein, and body mass index (BMI) (non-pregnancy) were measured. HbA1c levels significantly decreased in the second trimester of pregnancy and increased in the third trimester, while GA levels significantly decreased towards the third trimester. Casual plasma glucose levels decreased in the first trimester and subsequently remained constant. The reference intervals of GA and HbA1c in the healthy pregnant women were 11.5-15.7% and 4.5-5.7%, respectively. GA levels were lower (ρ<0.01) and HbA1c levels were higher (ρ<0.05) in pregnant women with proteinuria. In the obese group, GA levels were lower (ρ<0.01) than those of the control group (18.5≤ BMI <25kg/m2), and HbA1c levels were higher (ρ<0.01) than those of the control group. On the basis of the results of this multicenter study, the reference intervals of GA and HbA1c in healthy Japanese pregnant women were determined. Strict glycemic control is essential to reduce perinatal complications. GA appears to be a useful marker for pregnant women, since it can be measured easily and changes rapidly and markedly.
Masanori Nakata (Jichi Medical University)
Toshihiko Yada (Jichi Medical University)
Nucleobindin-2 (NUCB2)-derived nesfatin-1 located in the brain has been implicated in the satiety and control of energy metabolism. Nesfatin-1 is also produced in the periphery and present in the plasma. It has recently been reported that NUCB2/nesfatin-1 is localized in pancreatic islet β-cells in mice and rats and released from islets. However, its function in islets remains largely unknown. This study examined direct effects of nesfatin-1 on insulin release from pancreatic islets and on cytosolic Ca2+ concentration ([Ca2+]i) in single β-cells from ICR mice. In the presence of 8.3 mmol/L glucose, nesfatin-1 at 10-10-10-9 mol/L tended to increase and at 10-8 mol/L increased insulin release from isolated islets, while at 2.8 mmol/L glucose nesfatin-1 had no effect. Furthermore, nesfatin-1 at 10-10-10-8 mol/L increased [Ca2+]i in single β-cells in the presence of 8.3 but not 2.8 mmol/L glucose. The nesfatin-1-induced [Ca2+]i increase and insulin release were inhibited by removal of extracellular Ca2+ and by addition of nitrendipine, a blocker of voltage-dependent L-type Ca2+ channels. Unexpectedly, the [Ca2+]i responses to nesfatin-1 were unaltered by inhibitors of protein kinase A (PKA) and phospholipase A2 (PLA2). These results indicate that nesfain-1 potentiates glucose-induced insulin secretion by promoting Ca2+ influx through L-type Ca2+ channels independently of PKA and PLA2 in mouse islet β-cells.
Soushou Lee (Showa University)
Tsutomu Hirano (Showa University)
Impaired secretion of glucagon-like peptide 1 (GLP-1) has been suggested to contribute to the deficient incretin effect in patients with type 2 diabetes mellitus (T2DM). Recent studies, however, have not always supported this notion. Since Japanese patients with T2DM usually have severe impairment in the earlyphase of insulin secretion, the measurement of incretin secretions in Japanese T2DM patients would be useful for assessing the association between incretin levels and insulin secretion. We conducted an oral glucose tolerance test (75 g) (OGTT) and meal tolerance test (480 kcal) (MTT) for subjects with normal glucose tolerance (NGT, n=12), subjects with impaired glucose tolerance (IGT, n=7), and T2DM patients (n=21). The tests were carried out over 120-min study periods on separate occasions. Intact GLP-1, GIP, and dipeptidyl peptidase (DPP)-IV were measured by ELISA. T2DM exhibited an impaired early phase of insulin secretion and a reduction in glucagon suppression. There were no significant differences in GLP-1 or GIP levels at each sampling time among NGT, IGT, and T2DM after the ingestions; hence the incremental areas under the curve (IAUC) for the three groups were quite similar. The levels of DPP-IV, a limiting enzyme for the degradation of incretins, were comparable among the three groups. The GLP-1-IAUC was not correlated with IAUCs of insulin, C-peptide, or glucagon determined by the OGTT or the MTT. We concluded that intact GLP-1 levels are comparable between non-diabetics and T2DM, suggesting that impaired insulin secretion in Japanese T2DM is not attributable to defect in GLP-1 secretion.
Yasuhiro Ito (Kuma Hospital)
Recent studies have demonstrated that BRAFV600E mutation is a common event in papillary thyroid carcinoma and a majority of these lesions have shown a direct relationship between BRAFV600E mutation and aggressive characteristics, including a worse patient prognosis. However, there are no studies from Japan regarding this issue in a large series with adequate postoperative follow-up periods. We investigated BRAFV600E mutation in 631 patients with papillary carcinoma having median follow-up periods of 83 months. The prevalence of BRAFV600E mutation was 38.4%, and the rate was higher in carcinoma larger than 1.0 cm but did not successively increase with tumor size. Furthermore, the prevalence did not significantly increase in cases demonstrating high-risk biological features such as clinically apparent lymph node metastasis, massive extrathyroid extension, advanced age, distant metastasis at surgery, and advanced Stage. The disease-free survival of patients with BRAFV600E mutation did not differ from that of those without BRAFV600E mutation. These findings indicate that, although BRAFV600E mutation may play some roles in local carcinoma development, there is no evidence that BRAFV600E mutation significantly reflects the aggressive characteristics and poor prognosis of patients with papillary carcinoma in Japan.
Kazutomi Yoshiuchi (Osaka University)
Munehide Matsuhisa (The University of Tokushima)
To determine the impact of blood glucose profile, involving fluctuation and excursion of blood glucose levels, on glycated proteins, we evaluated the association among the daily profile of blood glucose, and glycated albumin (GA) and HbA1c levels in patients with type 1 diabetes (n = 93) and type 2 diabetes (n = 75). GA levels were strongly correlated with HbA1c levels in type 1 (r = 0.85, P<0.0001) and type 2 diabetes (r = 0.61, P<0.0001), respectively. HbA1c levels were similar between patients with type 1 and type 2 diabetes, while GA levels were significantly higher in type 1 diabetes. Thus the ratio of GA levels to HbA1c levels was significantly higher in type 1 diabetes than that in type 2 diabetes (3.32 0.36 vs. 2.89 0.44, p<0.001). The degrees of GA levels and HbA1c levels correlated with maximum and mean blood glucose levels in patients with type 1 and type 2 diabetes. Stepwise multivariate analysis revealed that GA levels independently correlated with maximum blood glucose levels in type 1 diabetes (F = 43.34, P<0.001) and type 2 diabetes (F = 41.57, P<0.001). HbA1c levels also independently correlated with maximum blood glucose levels in type 1 diabetes (F = 34.78, P<0.001), as well as being correlated with mean blood glucose levels in type 2 diabetes (F = 11.28, P<0.001). In summary, GA could be a better marker for glycemic control than glycated hemoglobin in diabetic patients, especially for evaluating glycemic excursion, which is considered to be a major cause of diabetic angiopathy.
Keiko Nishida (University of Occupational and Environmental Health)
Tumor necrosis factor-alpha (TNF-alpha) plays an important role in forming atherosclerosis based on chronic inflammatory condition in vivo and animal models. In human system, it is not clear the involvement of TNF-alpha to atherosclerosis. To clarify the relevance of TNF-alpha to atherosclerotic factors in human, We performed a prospective cohort study to investigate the inhibition of TNF-alpha with anti-TNF-alpha antibody infliximab may contribute to increase serum adiponectin levels, adipocyte-derived hormone with antiatherogenic properties, in patients with RA. 97 patients with active RA had been treated every 8 weeks for 1 year(13 men and 84 women, 54.2 ± 12.6 years, disease duration; 8.5 ± 1.5 years). They received a fixed dose of infliximab of 3 mg/kg every 8 weeks for 52 weeks. We evaluated changes of inflammatory markers, high molecular weight form of adiponectin levels and blood lipid levels. We also studied the association between increment rate of serum adiponectin and improvement of disease activity and inflammatory markers. Infliximab were strikingly dropped inflammatory markers (p<0.01), increased total cholesterol (TC) and high-density lipoprotein cholesterol (HDL-C) (p<0.05). Besides, serum adiponectin significantly increased, independent of RA activity and clinical backgrounds, suggesting that TNF-alpha and adiponectin exhibit opposite effects in human body. TNF-alpha blockade may interfere in the atherosclerosis directly or indirectly, by increasing serum adiponectin levels, therefore TNF-alpha blockade may improve cardiovascular morbidity and mortality in chronic inflammatory disease such as RA.
Tadashi Yamakawa (Yokohama City University)
Colestimide is a new anion-exchange resin used to lower serum cholesterol in Japan. Because of its excellent compliance, colestimide can replace cholestyramine. To clarify the effect of colestimide on glycemic controls, colestimide (3 g/day) or pravastatin (10 mg) was given orally to patients with type 2 diabetes treated with oral hypoglycemic agents or insulin who had low-density lipoprotein (LDL) cholesterol levels exceeding 3.6 mmol/l. In the colestimide groups, fasting plasma glucose concentrations had decreased significantly from 8.5 ± 1.4 to 7.7 ± 1.5 mmol/l at 3 months (P<0.05), as had glycated hemoglobin (HbA1c) from 7.7 ± 0.7% to 6.8 ± 0.5%, for an 8% reduction (P<0.01). Fasting plasma glucose and HbA1c did not change in the pravastatin group. Total cholesterol and LDL-cholesterol decreased significantly (P<0.01) with either medication, with similar reduction rates for both drugs. Doses of oral hypoglycemic agents and insulin did not change during the study, and body weight remained stable. Considering that patients with type 2 diabetes often have hyperlipidemia, colestimide therapy may have a clinically useful dual action in such patients.
Masami Murakami (Gunma University)
Teruhiko Kondo (Gunma Paz College)
We studied the effect of exercise on circulating adipokine, high sensitivity C-reactive protein (hs-CRP), and metabolic parameters in obese young women. Ninety-six healthy Japanese young female students aged 18-23 years were studied. The longitudinal intervention study of a 7-month exercise training program (30-60 min/day, 60-70% HR-reserve, 200-400 kcal, 4-5 days/week) was performed in eight obese female students (BMI ≥25 kg/m2). Eight control female students (mean BMI = 22 kg/m2) were included in the follow-up study. Body weight, body mass index (BMI), percentage of body fat (%Fat), body fat mass, lean body mass, health-promoting lifestyle profile-scale (L-scale), Vo2max (maximal oxygen uptake), hs-CRP, lipids, insulin homeostasis model assessment (HOMA-R), fasting levels for circulating adiponectin, leptin, and TNF-α, were measured before and after the exercise program. In obese subjects, body weight, BMI, %Fat, body fat mass, lean body mass, hs-CRP, leptin, and TNF-α were significantly higher, and L-scale and adiponectin were lower than those in control subjects. In obese subjects, exercise decreased body weight, BMI, %Fat, body fat mass, lean body mass, hs-CRP, leptin, and TNF-α, and increased L-scale, Vo2max, HDL-cho, and adiponectin. It was concluded that changes in circulating adipokine levels are involved in the improvement of the metabolic state by exercise and may be useful markers for evaluation and prescription of exercise.
Kumiko Hamano (Shonan Kamakura General Hospital)
Pulse wave velocity (PWV) is known to represent arterial stiffness and is established as a marker for cardiovascular risk and a prognostic factor for mortality in the case of chronic renal failure or hypertension. The application of an automated apparatus for measuring brachial-ankle pulse wave velocity (baPWV) has made PWV measurement non-invasive, easier to screen for cardiovascular risk and as a result, baPWV measurements have become widely applied in clinical practice in recent years. We assessed the baPWV in 7 flank hypothyroidism patients and 28 subclinical hypothyroidism patients. In comparison with age matched healthy controls, 3 hypothyroid patients had advanced values and by replacement therapy, all 7 subjects showed improvement in their baPWV values (1531.2 ± 242.7 to 1330.2 ± 208.6 cm/s, P<0.05). In 28 subclinical hypothyroid subjects, 71% also had accelerated baPWV values for their age. Ten subjects (36% of all) had neither hypertension, hyperlipidemia, diabetes nor were taking any medication, and yet 8 patients out of 10 showed advanced baPWV values compared to age matched mean values. The baPWV was not correlated to TSH or total cholesterol levels, and was associated with only age and blood pressure (p = 0.01, <0.001, respectively), which are widely demonstrated as the characteristics for baPWV. In two subclinical hypothyroid subjects, who were normotensive and had no dyslipidemia, thyroxine treatment was performed and the baPWV decreased with unchanged blood pressure and total cholesterol levels. We concluded that the arterial wall stiffness tends to be increased in both overt and subclinical hypothyroid patients, and an appropriate treatment could reverse the abnormalities. It is possible that the initiation of adequate treatment in subclinical hypothyroidism may reduce the cardiovascular risk.
Emina Itoh (Tokyo Women's Medical University)
The purpose of this study carried out at a single institute in Japan was to investigate the clinical characteristics and complications of patients with adult growth hormone deficiency (GHD). Clinical and biochemical data of 110 patients (50 males, 60 females; mean age 42 ± 17 yr) with adult GHD who attended Tokyo Women's Medical University between 1990 and 1999 were analyzed retrospectively from medical records. This retrospective analysis demonstrated that 109 patients had multiple pituitary hormone deficiencies, with 98 patients having a deficiency of more than three hormones. Sixty-one patients had childhood onset GHD (COGHD) while the remaining 49 patients had adulthood onset GHD (AOGHD). Body mass index (BMI) ranged from 16.9 to 35.9 with a mean of 23.9 ± 4.1 (kg/m2), with BMI being ≥ 25 kg/m2 in 38 patients (31% of COGHD and 38% of AOGHD). Forty-one percent of the patients had hypercholesterolemia, 41% had hypertriglyceridemia, 47% had decreased levels of HDL cholesterol and 48% had increased levels of LDL cholesterol. Intima-media thickness (IMT) of the carotid arteries was investigated in 33 patients, with abnormal findings including increased IMT or plaque being observed in 4 of 18 COGHD patients and 4 of 15 AOGHD patients. Diabetes mellitus and impaired glucose tolerance was found in 4 COGHD patients and 16 AOGHD patients. Insulin resistance was assessed in 36 patients by the homeostasis model insulin resistance index (HOMA-R) and ranged from 0.65 to 10.58 with a mean of 2.80 ± 0.37. This mean value of HOMA-R was significantly greater than that measured in normal subjects (1.58 ± 0.05: P<0.05). These data suggest that abnormal lipid and glucose metabolism, and atherosclerotic changes occur frequently in adult patients with GHD. Insulin resistance may play a role in glucose and lipid metabolism disorders associated with GHD.
Satoko Yamada (Gunma University)
Adenovirus-mediated gene transfer of pancreatic duodenal homeobox transcription factor PDX-1, especially its super-active version (PDX-1/VP16), induces the expression of pancreatic hormones in murine liver and reverses streptozotocin-induced hyperglycemia. Histological analyses suggest that hepatocytes are the major source of insulin-producing cells by PDX-1 gene transfer, although the conversion of cultured hepatocytes into insulin-producing cells remains to be elucidated. The present study was conducted to address this issue. Hepatocytes were isolated from adult rats. Then, PDX-1 or PDX-1/VP16 gene was introduced by using adenovirus vector. Two days later, the expression of insulin was detected at mRNA and protein levels. Transfection of PDX-1/VP16 was more efficient in converting hepatocytes to insulin-producing cells. Immunoreactivity of albumin was downregulated in transdifferentiated cells and some of them almost completely lost albumin expression. During the course of transdifferentiation, upregulation of mRNA for CK19 and α-fetoprotein was observed. When cultured in collagen-1 gel sandwich configuration, hepatocytes maintained their mature phenotype and did not proliferate. In this condition, transfer of PDX-1/VP16 also induced the expression of insulin. These results clearly indicate that hepatocytes possess a potential to transdifferentiate into insulin-producing cells in vitro.
Shun Soneda (St. Marianna University School of Medicine)
The prevalence of undermasculinized external genitalia has increased in several countries including Japan, and this phenomenon has primarily been ascribed to the deleterious effects of environmental endocrine disruptors such as dioxins. To examine a possible role of the genetic susceptibility to dioxins in the development of micropenis (MP), we studied the Arg554Lys polymorphism of the gene for aryl hydrocarbon receptor (AHR) and the Pro185Ala polymorphism of the gene for aryl hydrocarbon receptor repressor (AHRR), in 73 boys with MP (34 boys with mild MP from -2.1 to -2.5 SD and 39 boys with severe MP below -2.5 SD) and 80 control males (50 boys and 30 fertile adult males). The allele and genotype frequencies of the AHR polymorphism were comparable between the two groups of males, but those of the AHRR polymorphism were significantly different, with the Pro allele and the Pro/Pro genotype being more frequent in boys with MP than in control males (P-value: 0.0029 for the allele frequency and 0.011 for the genotype frequency). In addition, both polymorphisms were comparable in the allele and genotype frequencies between boys with mild MP and those with severe MP and between control boys and control fertile adult males. The results suggest that the AHRR Pro185Ala polymorphism may constitute a susceptibility locus for the development of MP in response to dioxins.
Hiroki Fujita (Akita University)
Decreased circulating levels of adiponectin, a novel adipose-derived adipocytokine, in obesity possibly contribute to the development of insulin resistance which is a major factor in the pathogenesis of type 2 diabetes. The present study was conducted to examine whether circulating and adipose tissue adiponectin levels are modulated by chronic treatment with metformin and intensive treatment with insulin in murine models of obesity and type 2 diabetes, db/db mice with a C57BL/KsJ genetic background. Nine-week-old male db/db mice were treated with metformin, insulin, and vehicle for 4 weeks. Expectedly, metformin treatment led to inhibition of weight gain and improvement of hyperinsulinemia. Insulin treatment lowered fasting blood glucose levels to normal values, although it sustained hyperinsulinemic state. However, after 4 weeks of treatment, serum adiponectin levels were not significantly elevated in either metformin-treated or insulin-treated db/db mouse group (14.2 ± 0.7 and 16.7 ± 1.0 μg/ml, respectively) compared to vehicle-treated group (14.9 ± 0.6 μg/ml). Similarly, adipose tissue adiponectin levels determined by Western blot analysis were not increased in either metformin-treated or insulin-treated group relative to vehicle-treated group. Recent studies have shown that adiponectin possibly has the same physiological effects on lipid and glucose metabolism that metformin has. Therefore, an elevation in blood concentration of metformin following the treatment might lead to suppression in adiponectin synthesis in adipose tissue, independent of inhibition in weight gain and improvement in hyperinsulinemia by metformin treatment. The present results indicate that adiponectin is not involved in the mechanism by which metformin treatment enhances insulin sensitivity. Moreover, our results suggest that adiponectin synthesis in adipose tissue may be suppressed under hyperinsulinemic state sustained by insulin treatment, even though hyperglycemia is markedly reduced. We conclude that antidiabetic treatment with metformin and insulin does not affect circulating and adipose tissue adiponectin levels.
Mariko Murase (Yokohama City University)
In order to compare the mechanism for the down regulation of the mRNA expression of pituitary receptors induced by GnRH antagonist (GnRHant) to that by GnRH agonist (GnRHa), we examined the effects of GnRHant (Cetrorelix, 333 μg/kg/day), GnRHa (leuprolide depot, 333 μg/kg), and GnRHant combined with GnRHa on LH response to exogenous GnRH, pituitary LH content, LHβ subunit mRNA, and GnRH receptor (GnRH-R) mRNA levels at 2, 5, 24, 72 hours, and 7 days after the treatment in ovariectomized rats. GnRHant significantly decreased serum LH, the LH response of the pituitary to exogenous GnRH, and the pituitary LH content compared to the control treatment, though GnRHa significantly increased serum LH. GnRHant with GnRHa significantly diminished the GnRHa-induced flare-up phenomenon. GnRHant significantly decreased LHβ mRNA and GnRH-R mRNA levels, but the magnitude of the decrease in these mRNA levels by GnRHant was significantly less than those by GnRHa until 72 hours following treatment. Prolonged treatment of GnRHant caused a marked inhibition of LHβ mRNA and GnRH-R mRNA expression, similar to that caused by GnRHa. Combination treatment with GnRHa and GnRHant was demonstrated to decrease LHβ mRNA and GnRH-R mRNA levels as much as GnRHa alone and GnRHant alone over 7 days of the treatment. The present study showed differences between GnRHant and GnRHa treatment in the reduction of GnRH-R mRNA levels up to 72 hours after the treatment, and indicated that the suppression of GnRH-R mRNA by GnRHant was the maximal by GnRHa 7 days after the treatment because more profound suppression was not observed upon additional treatment with GnRHa. The findings in the present study support the hypothesis that the mechanism by which GnRHant leads to down-regulation of the mRNA expression of pituitary receptors is similar to that of GnRHa.
Takeki Ogata (Gunma University)
The present study was conducted in an attempt to treat streptozotocin (STZ)-induced hyperglycemia by transplanting β cells derived from pancreatic ductal cells. Ductal cells obtained from neonatal rats were cultured in vitro. Approximately 70% of the cells were converted to insulin-secreting cells by incubating with betacellulin and activin A. Differentiated cells responded to a depolarizing concentration of potassium, tolbutamide and a high concentration of glucose, and insulin secretion increased by 2.5-, 2.3- and 1.6-fold, respectively. We then prepared pseudoislets using the differentiated cells, which exhibited greatly improved glucose-responsiveness, with a high concentration of glucose inducing a 3-fold increase in insulin secretion. We transplanted these pseudoislets into the portal vein of STZ-treated nude mice. Before transplantation, the plasma glucose concentration was above 400 mg/dl, and after transplantation it was markedly reduced, the effect of which persisted for two weeks. These results indicate that STZ-induced hyperglycemia can be treated by transplanting pseudoislets consisting of β cells derived from ductal cells.
Maki Fukami (National Research Institute for Child Health and Development)
Although gonadal estrogens are known to facilitate the development of skeletal lesion in SHOX haploinsufficiency, controversy exists as to whether gonadal estrogens are disadvantageous to pubertal growth. To clarify this matter, we analyzed growth pattern in 31 Japanese patients with a normal karyotype and molecularly confirmed SHOX haploinsufficiency. The mean height SD score at the diagnosis of SHOX haploinsufficiency was similar between patients identified in childhood and those identified in adulthood (-2.7 ± 0.8 [n = 15] vs. -2.4 ± 0.7 [n = 16], P = 0.36), and was significantly lower in patients identified by the studies for short stature than in those ascertained by the familial studies of the probands both in childhood (-3.0 ± 0.6 [n = 11] vs. -1.8 ± 0.5 [n = 4], P = 0.0051) and in adulthood (-3.0 ± 0.9 [n = 5] vs. -2.2 ± 0.5 [n = 11], P = 0.040). Analysis of longitudinal paired growth data obtained in seven females showed a significantly different mean height SD score between childhood and adulthood (-2.3 ± 0.5 vs. -2.9 ± 0.8, P = 0.0060). The results imply that gonadal estrogens have a deleterious effect on pubertal growth in SHOX haploinsufficiency, and that the growth disadvantage is recognizable by longitudinal rather than cross-sectional growth studies.
Rie Sasaki (Keio University)
We report on a 2 years and 9 months old Japanese boy with adrenal hypoplasia and mental retardation (MR) (developmental quotient ∼60) which occurred in the absence of severe adrenal crisis and resultant brain damage. Cytogenetic and molecular studies were performed in this boy and his parents with normal phenotype, showing that the boy had a maternally derived ∼2 Mb interstitial Xp deletion involving DAX1 (DSS-AHC critical region on the X chromosome, gene 1) for adrenal hypoplasia congenita and disrupting IL1RAPL (interleukin-1 receptor accessory protein-like) for non-specific MR. The results explain the development of MR in this boy in terms of contiguous gene syndrome, and suggest the importance of IL1RAPL analysis in patients with adrenal hypoplasia and MR.
Koji Shiraishi (Yamaguchi University)
Fertile eunuch syndrome is caused by isolated LH deficiency, but its pathophysiology still remains controversial. We report a case of fertile eunuch syndrome with homozygous Trp8Arg and Ile15Thr mutations in the LH β subunit gene. An 18-year-old man was admitted to our hospital for hypogonadism. Examination of genitalia revealed Tanner G1PH1, whereas both testes were elastically palpated and developed up to 18 ml. Endocrinological evaluations revealed normogonadotropic hypogonadism and there were normal responses after GnRH and hCG stimulation. Intratesticular testosterone concentration was almost normal (1.34 × 103 ng/g). By PCR direct sequencing, homozygous Trp (8) Arg and Ile (15) Thr mutations in exon 2 of LH β were detected. Normal virilization and improved semen parameters were achieved after hCG supplementation. To our knowledge, this is the first case of fertile eunuch syndrome with homozygous Trp (8) Arg and Ile (15) Thr mutations in β subunit of LH gene.
Hideki Yamasaki (Kagoshima University)
A 31-year-old regularly menstruating Japanese female was referred to our outpatient clinic by a psychiatrist. She had been diagnosed as having gender identity disorder by detailed counseling and clinical intervention 3 years earlier. After obtaining fully informed written consent, we treated her with 125 mg of testosterone enanthate, intramuscularly, every 2 weeks for 4 months. Serum testosterone levels increased to the normal male value (from 28 to 432 ng/dL). Although menstrual cycle remained regular, her voice became lower after 4 months of therapy. Body weight, body mass index, and lean body mass increased, while body fat mass and percentage of body fat decreased. However, trunk-leg fat ratio did not change during the observation period. During testosterone therapy, a disproportionate increase in lean body mass and decrease in body fat mass are early onset events, while the shift toward upper body fat distribution may be a late onset event along with increase in BMD.
Nobuyuki Asanuma (Osaka University)
We established a new analytical system in which functioning cells were transplanted directly into the pancreas and liver. The retrograde transplantation of beta cell line, Min6 cells, into the streptozotocin-diabetic mice normalized plasma glucose and insulin levels. The injected cells were protected from pancreatic enzymes with enzyme inhibitor. Blood glucose decreased gradually over 10 days and the diabetic mice recovered weight at the same time. Intraperitoneal glucose tolerance test showed that the peak of plasma glucose of the transplanted mice was less than half that of the control. The insulin secretion of the transplanted mice was recovered and stimulated 4.6 times from the basal secretion. Histological analyses showed that the pancreas and liver were characterized by Min6 cell clusters dispersed throughout the organs. Min6 cells were detected near the pancreatic or bile ducts. It is suggested that the injected cells obstructed the peripheral ducts where they settled. The weight of pancreas and liver did not differ significantly in either Min6 transplanted or the control mice. The metabolic effects on the weights of these organs appeared the same in both groups. This is the first report that cells transplanted via ducts into the pancreas and liver performed their biological function. Our transplantation model makes possible the in vivo analysis of the regeneration machinery of the pancreas and liver.
Naoya Nakai (Mie University)
The effects of diabetes and exercise training on the activity of pyruvate dehydrogenase (PDH) complex in skeletal muscle were examined in rats. Male Sprague-Dawley rats were divided into four groups as follows: non-diabetic sedentary, non-diabetic trained, diabetic sedentary, and diabetic trained groups. Diabetic rats were prepared by a boulus injection of intravenous streptozotocin (50 mg/kg body weight). Exercise training was performed by having rats run on a treadmill at a speed of 25 m/min for 45 min/day, 6 days/wk for 4 wks. Exercise training decreased serum concentrations of glucose and non-esterified fatty acid in diabetic rats. GLUT4 content in skeletal muscle in sedentary rats was significantly decreased by diabetes; however, exercise training significantly increased the GLUT4 content in diabetic rats. The total and actual activities and the proportion of actual activity of the PDH complex were decreased in diabetic sedentary rats. Exercise training did not affect the total activity of the PDH complex in non-diabetic rats, whereas it incresed the total activity in diabetic rats to the same level as that in non-diabetic rats. In diabetic rats, exercise training tended to increase the proportion of actual activity of the PDH complex from 2.7 ± 0.4% to 4.7 ± 0.8%, although the proportion of actual activity in non-diabetic rats was decreased by exercise training. The present study suggests that exercise training may improve glucose metabolism in the skeletal muscle of streptozotocin-induced diabetic rats probably through the mechanisms of increasing both GLUT4 content and the activity of the PDH complex.
Natsuko Yokoi (Yokohama City University)
The objective of this study was to compare, in infertile women suffering from severe hypogonadotropic amenorrhea, the therapeutic utility and the incidence of complications arising from fertility treatment by the conventional human menopausal gonadotropin/human chorionic gonadotropin (hMG-hCG) method, the hMG step-down method, the sequential hMG/gonadotropin-releasing hormone (GnRH) method and a new, modified hMG-GnRH method that has been developed by us. In the step-down method, the daily dose of hMG was decreased from 150 IU to 75 IU when the follicle diameter reached 11-13 mm. In the sequential hMG-GnRH, hMG injection was switched to pulsatile GnRH administration (20 μg/120 min SC), when the follicle diameter reached 11-13 mm. In our new modified hMG-GnRH, pulsatile GnRH was injected together with hMG. Daily hMG was stopped and the GnRH dosage was changed from 10 μg to 20 μg when the follicle diameter reached 11-13 mm. Initially, the three established methods were applied randomly to treat 34 cycles in 20 women; and subsequently, five patients who failed to conceive following treatment by sequential hMG-GnRH were then treated by the modified hMG-GnRH method. More than eight growing follicles and multiple pregnancies were observed during treatment by the conventional method. The incidence of ovarian hyperstimulation syndrome (OHSS) was 25.7% with the conventional method, 20.0% with the step-down method and 0% with the sequential hMG-GnRH method; however, the rate of ovulation was only 50% with the sequential hMG-GnRH method. By contrast, with the modified hMG-GnRH method, less than three growing follicles occurred in 81.8% of patients, there was a 100% rate of ovulation, and neither OHSS nor multiple pregnancies were observed. Moreover, the modified hMG-GnRH method induced pregnancy in 3 out of 5 patients. These data indicate that this new method is favorable for the treatment of severe hypogonadotropic amenorrhea.
Takako Shibayama (Chiba University)
We investigated the long-term estrogenic influence of genistein on the male reproductive system in mice. Newborn ICR male mice were treated with genistein (10, 100, or 1000μg/mouse) for neonatal 5 days. As positive control, administration of diethylstilbestrol (0.5-50μg/mouse) was carried out. In mice exposed to genistein, we examined weight of testes, sperm counts, sperm motility, and mRNA expression levels of estrogen receptor α (ERα) and androgen receptor (AR) at 4, 8 or 12 weeks after birth. Moreover, at 12 weeks of age, we evaluated protein level of ERα. In our conventional reproductive-toxicological study (weight of testes, sperm counts and sperm motility), neonatal transient exposure to genistein did not show adverse effects on the male reproductive system in 4, 8 or 12 week old mice. However, in mice treated with genistein mRNA expression levels of ERα and AR were reduced at 8 weeks. This reduction was recovered at 12 weeks in mice treated with a lower dose (10μg) of genistein but not in those with higher doses (100μg and 1000μg). In addition, ERα protein levels tended to decrease in 12 weeks of adulthood. Our results exhibited that the disruption of gene expression continued for long term such as 3 months after administration of genistein, even if no effect was found at conventional reproductive-toxicological level. We have shown that neonatal administration of weak estrogenic compound (genistein) affects male reproductive organs at molecular levels in adulthood.
Yasuhide Tokukoda (Kobe University)
There is accumulating evidence that interleukin-1 (IL-1) levels are increased locally at the site of active bone resorption in a variety of diseases including osteoporosis, periodontal disease and rheumatoid arthritis. However, the pathogenic role of IL-1 in bone loss remains to be fully elucidated. We present here additional evidence that IL-1β enhances endothelial activation and thereby stimulates mobilization of peripheral blood mononuclear cells (PBMCs) from luminal to abluminal spaces across the endothelium. Furthermore, IL-1β stimulates the differentiation of PBMCs into osteoclast-like cells with bone-resorbing activity in the presence of human osteoblastic SaOS-2 cells without systemic hormones. These findings provide circumstantial evidence for the hypothesis that IL-1β generated in the bone microenviroment plays a stimulatory role in PBMC mobilization from the peripheral circulation and their subsequent differentiation into osteoclast-like cells in the bone tissue. In addition, the present study supports the notion that osteoclast progenitor cells might be derived from the peripheral circulating blood mononuclear cells in human.
Junko Miyamoto (Tokyo Metropolitan Kiyose Children's Hospital)
Development of Growth Hormone and Adrenocorticotropic Hormone Deficiencies in Patients with Prenatal or Perinatal- Onset Hypothalamic Hypopituitarism Having Invisible or Thin Pituitary Stalk on Magnetic Resonance Imaging
A gradual loss of anterior pituitary hormones is suspected in patients treated with irradiation due to brain tumors. Development of growth hormone deficiency (GHD) with age has been documented in patients with idiopathic GHD. A gradual loss of adrenocorticotropic hormone (ACTH) secretion has been also shown in a patient with severe GHD and an invisible pituitary stalk on magnetic resonance imaging (MRI). The purpose of this longitudinal and cross-sectional study was to evaluate the gradual loss of growth hormone (GH) and ACTH in a homogeneous group of patients with hypopituitarism. Twenty-eight patients (23 males, 5 females) from four hospitals were diagnosed as having prenatal or perinatal-onset hypothalamic hypopituitarism. They had an abnormal pituitary stalk on MRI (invisible in 18 patients, thin in 10 patients) without any other organic disease of the brain. Each patient had GHD upon initial evaluation. Height (n=20) was analyzed as standard deviation score (SDS). Longitudinal (n=8) and cross-sectional (n=28) GH secretion capacity was evaluated by GH peaks, in response to insulin tolerance test (ITT) and growth hormone releasing factor test (GRF test). Longitudinal (n=10) and cross- sectional (n=28) ACTH secretion capacity was evaluated by cortisol peaks in response to ITT. Height SDS decreased each year in all the untreated patients after birth. GH peaks decreased gradually with age. Longitudinal data showed decreased GH peaks with age in seven out of eight patients using ITT and in all four patients using GRF tests. Cortisol peaks also decreased gradually together with signs and symptoms for adrenal deficiency such as general fatigue. Cortisol peaks of less than 414nmol/L (15μg/dl) in response to ITT were seen in 24% of the tests before age 10 and 56% before age 25. In conclusion, GHD and ACTH deficiency developed gradually in patients with prenatal or perinatal-onset hypothalamic hypopituitarism who had invisible or thin pituitary stalks examined by MRI.
Kazutaka Aoki (Yokohama City University)
Dehydroepiandrosterone (DHEA) is known to improve hyperglycemia of diabetic C57BL/KsJ-db/db mice that are obese and insulin resistant. In a previous study, we reported that DHEA as well as troglitazone suppresses the elevated hepatic gluconeogenic enzymes, glucose-6-phosphatase (G6Pase) and fructose-1, 6-bisphosphatase (FBPase) activities in C57BL/KsJ-db/db mice. In the present study, we evaluated the changes in mRNA of G6Pase and FBPase in db/db mice. Despite hyperinsulinemia, the G6Pase mRNA level of db/db mice was elevated as compared to their heterozygote littermate db/+m mice. In contrast, the FBPase mRNA level was not elevated in db/db mice. Administration of DHEA for two weeks significantly decreased the blood glucose level and the elevated G6Pase mRNA level in db/db mice. No significant changes were seen in the FBPase mRNA level after the administration of DHEA. Administration of troglitazone also decreased the blood glucose and G6Pase mRNA level in db/db mice although no changes were seen in the FBPase mRNA level. These results suggest that the elevation of G6Pase mRNA is important in elucidating the cause of insulin resistance, and that the G6Pase gene is at least one target for the hypoglycemic effects of DHEA as an insulin sensitizing agent in db/db mice.
Taichi Sekine (St. Marianna University School of Medicine)
To elucidate the involvement of intrathyroidal T cells in the thyroid antigen-specific immune response in Graves' disease (GD), we investigated whether identical T cell clonotypes accumulate clonally in the right and left lobes of thyroid glands of GD patients. mRNAs extracted from thyroid glands of five females patients with GD were reverse-transcribed to cDNA and then the genes coding the T cell receptor B chain variable (V-NDN-J) region were amplified using polymerase chain reaction. Single strand conformation polymorphism analysis and subsequently nucleotide sequencing were also performed to determine the clonotype of accumulating T cells. T cells infiltrating the thyroid glands showed oligoclonal expansion. The expanded T cell clonotypes were not detected in peripheral blood of the same patients. Importantly, the majority of expanding T cell clonotypes in the two lobes of the thyroid glands were identical. Our findings suggest that the clonal expansion of identical T cell clonotypes in the two lobes is driven by factors common to both lobes, such as thyroid-specific antigens, in patients with Graves' disease.
Tomohiro Someya (Chiba University)
Persistent hyperinsulinemic hypoglycemia of infancy (PHHI) is a genetic disorder characterized by unregulated insulin secretion and profound hypoglycemia. Recently, mutations of SUR1 and Kir6.2, which constitute the pancreatic β-cell ATP-sensitive potassium (KATP) channel, have been shown to be associated with familial PHHI in certain ethnic groups. In the present study, we examined clinical symptoms, therapy, and variations in the SUR1 and Kir6.2 genes in eight Japanese patients with PHHI. Four patients were being treated with pharmacological agents and the other four had required pancreatectomy to normalize glucose levels. There was no difference in timing of the onset of hypoglycemia between the groups. There also was no difference in severity between the two groups, as assessed by blood glucose levels, plasma insulin levels, and birth weight. However, all of the pancreatectomized patients and none of the medically treated group had presented with seizures. By genetic screening, we found eleven nucleotide substitutions in the SUR1 gene, three of which result in amino acid changes, and three nucleotide substitutions in the Kir6.2 gene, two of which result in amino acid changes, but all of these genetic variants had been previously reported in normal subjects. These results indicate that the mechanism of hypoglycemia in these patients is different from those previously reported in PHHI patients, giving further support to the view that PHHI is a heterogeneous disorder.