This review summarizes new findings related to beneficial effects of melatonin (N-acetyl-5-methoxytryptamine) on reproductive physiology. Recently many researchers have begun to study the local role of melatonin as an antioxidant. We focused on intra-follicular role of melatonin in the ovary. Melatonin, secreted by the pineal gland, is taken up into the follicular fluid from the blood. Reactive oxygen species (ROS) are produced within the follicles, during the ovulatory process. Melatonin reduces oxidative stress as an antioxidant, and contribute to oocyte maturation, embryo development and luteinization of granulosa cells. Our clinical study demonstrated that melatonin treatment for infertile women increases intra-follicular melatonin concentrations, reduces intra-follicular oxidative damage, and elevates fertilization and pregnancy rates. Melatonin treatment also improves progesterone production by corpus luteum in infertile women with luteal phase defect. Melatonin treatment could become a new cure for improving oocyte quality and luteal function in infertile women.

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One of human GLP-1 analogues, liraglutide has been approved as adjuvant therapy to oral medication in T2DM. It was also shown to prevent diabetes in obese subjects and rats. However, it is unknown whether liraglutide can effectively mitigate the effects of prediabetes. We therefore investigate this by treating 12-weeks old Otsuka-Long-Evans-Tokushima fatty (OLETF) rats with liraglutide 50, 100, and 200 μg/kg, respectively twice a day for 12 weeks. Eight Long-Evans-Tokushima-Otsuka (LETO) rats with saline injection served as normal controls. Body weight, food intake, lipid profiles, inflammatory markers (fibrinogen, Hs-CRP, IL-6, TNFα, and PAI-1), glycemic metabolism and insulin sensitivity, and apoptotic factors (Bcl-2 and Bax) expression were monitored. We found that 12-week old OLETF rats had significantly increased body weight, food intake, serum levels of lipid profiles, inflammatory markers, and insulin compared to LETO rats. FPG level was significantly increased but still lower than 7mmol/L without impaired glucose tolerance (IGT). After 12 weeks, vehicle-treated OLETF rats had further deterioration in IFG, IGT, insulin resistance, lipid profiles, and inflammatory state. Pancreatic islets were hypertrophic with distorted structure, scarring, and inflammatory cell infiltration. However, in the three liraglutide-treated groups, IFG, IGT, the increased lipid profiles and inflammatory markers were reversed. Insulin resistance was similar to the level before the treatment. Moreover, liraglutide restored the islet structure, up-regulated Bcl-2 expression and down-regulated Bax expression. It indicated that liraglutide could suppress diabetes onset in OLETF rats with prediabetes, probably by reserving β cell function via regulating apoptotic factors as well as ameliorating lipid metabolism and inflammatory reactions.

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In patients with acromegaly, cardiovascular diseases are the most common cause of death. Arterial stiffness is increasingly recognized as a valuable surrogate marker for predicting cardiovascular events. To evaluate the vascular status of acromegalic patients, we used the cardio-ankle vascular index (CAVI) to reflect the arterial stiffness from the heart to the ankles. We analyzed 21 acromegalic patients, comprising five patients with untreated active acromegaly, one patient treated with medication and 15 patients who underwent transsphenoidal surgery. Among the 15 patients with surgery, 10 received additional therapies with dopamine agonists and/or somatostatin analogs. All patients with acromegaly unexpectedly showed significant reductions in the CAVI, indicating reduced arterial stiffness, compared with age- and sex-matched controls, regardless of whether they underwent surgery. There was a significant negative correlation between the CAVI and the serum insulin-like growth factor (IGF)-I level in these patients. Active acromegalic patients were associated with lower CAVI than controlled patients. Sequential measurements of the CAVI and serum IGF-I before and after treatment with octreotide and transsphenoidal surgery revealed that a reduced IGF-I level after treatment was accompanied by CAVI elevation. The present findings indicate that the CAVI is negatively correlated with the serum IGF-I level in acromegaly. These findings are consistent with previous reports indicating that the GH/IGF-I axis reduces peripheral vascular resistance. This non-invasive assessment can reflect the present vascular status and would be a useful marker for evaluation of therapeutic effects in patients with acromegaly.

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Chemerin, a recently discovered adipocytokine plays an important role in obesity and obesity-associated metabolic complications. However, the role of chemerin in the pathogenesis of type 2 diabetes mellitus (T2DM) has not fully been elucidated. We compared the serum chemerin levels and metabolic parameters between 88 control subjects, 86 patients with metabolic syndrome (MS), and 147 patients with T2DM in a Japanese population and further analyzed their correlation. Enzyme-linked immunosorbent assay was used to measure the serum chemerin levels. The chemerin levels were significantly higher in male than in female control subjects (p < 0.005), with significant decreases in patients with T2DM compared with those with MS and control subjects (164.9 ± 6.3 ng/mL vs. 209.8 ± 7.7 and 218.7 ± 7.3 ng/mL; p < 0.0001 vs. p < 0.0001, respectively) but no significant differences in female subjects. The multiple regression analysis revealed that the chemerin levels negatively correlated with the fasting glucose and HbA1c levels in total and male subjects. In the patients with T2DM, the chemerin levels negatively correlated with fasting glucose and high-density lipoprotein cholesterol but positively correlated with body mass index (BMI), and total cholesterol and triglyceride levels. The negative correlation between the chemerin and fasting glucose levels remained significant after adjustment for age, sex, and BMI in the total and male subjects and those with T2DM. These results suggest the role of chemerin in sex dimorphism and a potential link between chemerin levels and T2DM pathogenesis in a Japanese population.

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In order to investigate the factors contributing to the glucose-lowering effect of vildagliptin, we analyzed the results of the oral glucose tolerance test together with several clinical parameters in Japanese patients with type 2 diabetes before and after 24 weeks of treatment with vildagliptin. The data of the 13 patients who satisfactorily completed the follow-up examinations were included. After 24 weeks treatment with vildagliptin, the patients were classified into a responder group (69.2%) and a non-responder group (30.8%); the responders consisting of subjects whose HbA1c decreased following 24 weeks treatment with vildagliptin, and the non-responders consisting of subjects who did not show any significant decrease of HbA1c. There were no differences in baseline characteristics between the two groups before administration of vildagliptin. After 24 weeks of treatment, HbA1c was significantly reduced from 7.3 ± 0.5% to 6.7 ± 0.5% in the responder group (P = 0.0077), while it tended to rather increased from 7.1 ± 0.6% to 7.5 ± 0.7% in the non-responder group (P = 0.0679). Also, parameters reflecting the glucose-stimulated insulin secretion, such as the insulinogenic index and oral disposition index, were significantly higher in the responder group than in the non-responder group, whereas insulin sensitivity was similar between the two groups. These results suggest that the difference in the degree of improvement of the glucose tolerance between the responder group and non-responder group in this study could be associated with the effect of vildagliptin on the glucose-stimulated insulin secretion, but not on the insulin sensitivity.

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Isolated hypoaldosteronism is a rare and occasionally life-threatening cause of salt wasting in infancy. A 2-month-old Japanese boy of unrelated parents was examined for failure to thrive and poor weight gain. Laboratory findings were hyponatremia, hyperkalemia, high plasma renin and low aldosterone levels. Spot urine analysis by gas chromatography-mass spectrometry (GC-MS) showed that urinary excretion of corticosterone metabolites was elevated. Whereas excretion of 18-hydroxycortricosterone metabolites was within the normal range, excretion of aldosterone metabolites was undetectable. The patient was therefore suspected to have aldosterone synthase deficiency type 1. Sequence analysis of CYP11B2, the gene encoding aldosterone synthase (CYP11B2), showed that the patient was a compound heterozygote for c.168G>A, p.W56X in exon 1 and c.1149C>T, p.R384X in exon 7. p.W56X was inherited from his mother and p.R384X was from his father. Since both alleles contain nonsense mutations, a lack of CYP11B2 activity was speculated to cause his condition. To our knowledge, this is the first Japanese patient in which the molecular basis of aldosterone synthase deficiency type 1 has been clarified. This case also indicates that spot urinary steroid analysis is useful for diagnosis.

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This study assessed the effectiveness and safety of growth hormone (GH; Humatrope^®) therapy in Japanese children with GH deficiency (GHD) or Turner syndrome (TS) enrolled in the Genetics and Neuroendocrinology of Short Stature International Study (GeNeSIS). GeNeSIS is an open-label, multinational, multicenter, observational study conducted in 30 countries. In this interim report, there were 1129 GH treatment-naïve children with GHD, with a mean chronological age (± standard deviation) of 8.75 (3.32) years, and 90 girls with TS, with a mean chronological age of 8.93 (3.67) years. The mean height standard deviation score (SDS) increased from -2.73 (0.63) SD and -2.71 (0.63) SD at study entry to -2.22 (0.68) SD and -2.20 (0.60) SD after 1 year of treatment in the GHD and TS groups, respectively. In both groups, mean height SDS increased further with each year of treatment to 4 years; however, the magnitude of change in height SDS declined with time. The mean insulin-like growth factor-I SDS increased from below the mean of the reference population at study entry to a level similar to (GHD group) or higher than (TS group) the mean of the reference population during the 4-year treatment period. The incidence of serious adverse events (AEs), treatment-related AEs, and AEs related to glucose intolerance was low in both groups (0.1% to 3.0%). In conclusion, GH treatment in Japanese children with GHD or TS resulted in increased growth over a 4-year treatment period with a favorable safety profile; however, the improvements in growth declined with time.

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Apolipoprotein B-48 (ApoB-48) is a constituent of chylomicrons and chylomicron remnants, and is thought to be one of the risk factors for atherosclerosis. We evaluated the effect of L-thyroxine (L-T₄) replacement on serum ApoB-48 levels in patients with primary hypothyroidism. Eighteen patients with overt hypothyroidism (OH) and 18 patients with subclinical hypothyroidism (SH) participated in the study. The lipid profiles, including ApoB-48, were measured in patients with hypothyroidism before and 3 months after L-T₄ replacement. After L-T₄ replacement, the serum concentrations of all lipoproteins, exclusive of lipoprotein(a) (Lp(a)), were significantly decreased in patients with OH. In patents with SH, the serum levels of total cholesterol (TC), non-high-density lipoprotein cholesterol (non-HDL-C), remnant-like particle cholesterol (RLP-C), apolipoprotein B (ApoB), and ApoB-48 decreased significantly after L-T₄ replacement. The serum levels of triglycerides (TG), HDL-C, low-density lipoprotein cholesterol (LDL-C), apolipoprotein A1 (ApoA-1), and Lp(a) did not change significantly. In all 36 patients, the reduction in the ApoB-48 levels correlated significantly with the reduction in TSH levels (r = 0.39, P<0.05). This study showed clearly that L-T₄ replacement might reduce serum levels of ApoB-48 in both OH and SH patients. Such altered serum levels of ApoB-48 in patients with OH and SH may be related to the disturbed metabolism of chylomicron remnants in patients with hypothyroidism.

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YKL-40 is a marker of inflammation and endothelial dysfunction, both of which play important roles in the progression of diabetic complications. However, little information has been obtained about serum YKL-40 levels in type 1 diabetic patients. We evaluated YKL-40 levels and its association with diabetic micro- and macroandgiopathy in 131 young Japanese type 1 diabetic patients without advanced diabetic complications (aged 24.7±5.9 years) and 97 age- and gender-matched healthy controls. YKL-40 levels were significantly elevated in type 1 diabetic patients than in healthy controls (median (range) 46.4 (20.3-136.7) and 52.3 (21.4-274.1) ng/mL, respectively, p = 0.003). There was a significant positive association between YKL-40 levels and urinary albumin creatinine ratio (UACR) (r = 0.226, p = 0.013). Furthermore, a multivariate regression analysis demonstrated that YKL-40 levels were a determinant of UACR independently of conventional risk factors. In addition, YKL-40 levels were significantly higher in participants with diabetic retinopathy compared to those without it (median (range) 55.5 (23.3-274.1) and 50.3 (21.4-237.4) ng/mL, respectively, p = 0.039). Serum YKL-40 levels were elevated in type 1 diabetic patients and associated with increasing level of albuminuria. YKL-40 could be a predictor to assess the risk of diabetic microangiopathy in the early stage in type 1 diabetic patients.

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Fibroblast growth factor 23 (FGF-23) is known as a phosphaturic factor regulating phosphate homeostasis. Several studies suggest that dietary phosphate, serum phosphate and 1,25-dihydroxyvitamin D [1,25(OH)₂D] are candidate regulators of FGF-23. While the human studies, which modulated the dietary or serum phosphate showed in rather controversial results, manipulation of the active vitamin D definitely affected FGF-23 in animals. This study was conducted to elucidate the relationship between active vitamin D directly stimulated by ultraviolet B (UVB) exposure and FGF-23 level in human. Ten healthy young adults were recruited to get the UVB exposure thrice a week at sub-minimal erythemal dose with gradual increment by 10% only for 4 weeks. Serum calcium, phosphate, mineral-related hormones and bone turnover markers were analyzed before and after the UVB exposure every 4 week for 12 whole weeks. Twenty five-hydroxyvitamin D [25(OH)D] increased by 115% (19.8 ng/mL to 40.5 ng/mL, p < 0.001) after 4 weeks of UVB exposure. While 1,25(OH)₂D increased by 75% (49.9 pg/mL to 64.4 pg/mL, p < 0.001) then both level decreased after 4 weeks of withdrawal. C-telopeptide peaked at 2nd week then decreased, while osteocalcin increased gradually. FGF-23 started to increase from the 4th week of UVB exposure then significantly at the 4th week after withdrawal of UVB (27.8 pg/mL to 41.4 pg/mL, p < 0.05). UVB exposure effectively increased 1,25(OH)₂D with delayed stimulatory effect on FGF-23. This result could support the regulatory loop of 1,25(OH)₂D and FGF-23 in human, FGF-23 regulation by 1,25(OH)₂D.

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B-type natriuretic peptide (BNP) is produced by the heart and its plasma level is increased with the severity of left ventricular (LV) dysfunction/hypertrophy. The normal heart preferentially utilizes fatty acids as energy substrates. Plasma BNP levels are reported to be lower in obese individuals. We examined the relationship between BNP production and plasma free fatty acids (FFA), homeostasis model assessment of insulin resistance (HOMA-IR), and LV dysfunction/ hypertrophy. We examined the plasma BNP levels and FFA at the aortic root (AO) and coronary sinus (CS) as well as hemodynamic parameters in 62 patients (38 men and 24 women, 62.5±11.7 yrs) who underwent cardiac catheterization. Log BNP (AO) had a significant positive correlation with log BNP (CS-AO) (r=0.877, P<0.001). Log BNP(CS-AO) had a significant negative correlation with BMI (r=-0.558, P<0.001), waist circumference (WC) (r=-0.574, P<0.001), log FFA(AO) (r=-0.643, P<0.001), log triglyceride (r=-0.431, P<0.001), and log HOMA-IR (r=-0.463, P<0.001) and a significant positive correlation with left ventricular mass index (LVMI) (r=0.403, P=0.001). The multivariable regression analyses including log HOMA-IR, LVMI, and age as an independent variable revealed that HOMA-IR and LVMI were significant predictors of log BNP (CS-AO) or BNP production (P=0.001 and 0.004, respectively). We conclude that plasma BNP levels are determined primarily by cardiac production and that insulin resistance is a significant predictor of cardiac BNP production independent of LV hypertrophy in obese individuals.

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The arginine + GHRH test has been established as an alternative to the insulin tolerance test (ITT) for the diagnosis of adult GH deficiency (AGHD). However, the glucagon, arginine, and GH releasing peptide-2 (GHRP-2) test are recommended as alternatives in Japan. The objective of this study was to evaluate the arginine and GHRP-2 tests as alternatives to the ITT for the diagnosis of AGHD in a Japanese population. Three stimulation tests (ITT, arginine test, and GHRP-2 test) were conducted in 71 pre-operative adult patients with pituitary tumors (age, 18-65 years). The peak GH responses to each test were examined. The peak GH responses were significantly lower with the ARG test (median 4.43 μg/L) (p < 0.0001) than with the ITT (median 9.38 μg/L), and the peak GH responses with the GHRP-2 test (median 28.88 μg/L) were higher (p < 0.0001). However, among the AGHD patients, there was no significant difference between the peak GH responses to the ARG test and the ITT. The sensitivities and specificities of the ARG / GHRP-2 tests compared to the ITT for the diagnosis of severe AGHD (peak GH responses to ITT ≤ 1.8 μg/L) were 93.8% / 81.3% and 85.5% / 94.5%, respectively. The arginine and GHRP-2 stimulation tests are acceptable alternatives to the ITT for the diagnosis of AGHD in Japanese patients. The method and criterion for the diagnosis of AGHD should be reconsidered and adjusted to each population.

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Leprechaunism (Donohue syndrome) is the most severe type of insulin receptor (INSR) gene anomaly with the majority of patients surviving for only 2 years. We report a surviving 2 -year-old male with leprechaunism, bearing novel compound heterozygous mutations in the INSR. The patient is a Japanese boy with acanthosis nigricans, lack of subcutaneous fat, hirsutism, thick lips, gum hypertrophy and extremely high insulin levels (6702 mU/mL). He was as having identified novel compound heterozygous mutations in INSR (p.T910M and p. E1047K). At 24 day-old, recombinant human insulin-like growth factor 1 (rh-IGF1) treatment was started because of poor weight gain. At 2 years old, the patient’s serum glucose level and HbA1C value had worsened, and both a bolus of rh-IGF-1 and a subcutaneous injection of a rapid-acting insulin analog after meals, in addition to α-glycosidase inhibitor, were initiated from 2 years onward. Oxygen administration and biphasic positive airway pressure treatment were also initiated from 2 years old due to upper airway obstruction with adenoidal hypertrophy. In the experiments conducted using COS7 cells homozygously transfected with the INSR mutation, T910M INSR failed to process the proreceptor and decreased insulin-stimulated tyrosine phosphorylation. E1047K INSR resulted in a complete absence of insulin-stimulated tyrosine phosphorylation. These findings suggest the near absence of INSR in this patient. We consider that the rhIGF1 treatment contributed to his long survival, but it was not able to prevent his diabetic condition. Our report provides important insights into the function of INSR, and for the treatment of leprechaunism.

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It is well-known that papillary thyroid carcinoma (PTC) frequently metastasizes to the regional (central and lateral) lymph nodes, even though it is diagnosed as node-negative on preoperative imaging studies. In this study, we investigated predictors of microscopic node metastasis and lymph node recurrence of PTC without node metastasis detected preoperatively (N0). Of the clinicopathological features that can be evaluated pre- and intraoperatively, tumor size (> 2 cm) was the strongest predictor of microscopic central and lateral node metastasis on multivariate logistic analysis. Also, the tumor size most markedly affected lymph node recurrence, but not distant recurrence. Lymph node recurrence may not be immediately life-threatening, but it can be a stressor both for physicians and patients. Therefore, careful lymph node dissection is recommended for PTC with a large size, even though it is prophylactic.

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Adiponectin is divided into high-molecular-weight (HMW), middle-molecular-weight (MMW) and low-molecular-weight (LMW) types. While HMW adiponectin has been studied by many researchers, the roles of MMW and LMW adiponectin have not yet been sufficiently elucidated. In addition, there are conflicting findings regarding the role of adiponectin in chronic inflammatory diseases, especially asthma. Therefore, we compared patients who suffered episodes of asthma in the past (=asthmatics) with those who did not (=non-asthmatics) in order to investigate the relationship between asthma and HMW, MMW and LMW adiponectin. The subjects in this study included 76 university students. None of the subjects were smokers, on regular medications or seeing a doctor regularly at the time. Fourteen subjects reported past histories of asthma. We also measured and compared the levels of leptin and ghrelin to that of adiponectin, as these hormones are connected with inflammatory conditions. Although the physical data of the asthmatics were similar to those of the non-asthmatics, the levels of ghrelin and all fractions of adiponectin tended to be lower in the asthmatics than in the non-asthmatics. While the levels of MMW and LMW adiponectin in the asthmatics were found to be significantly low, the levels of ghrelin and HMW adiponectin were not clear. According to a multivariate regression analysis of the MMW and LMW adiponectin levels, asthma was found to be more significantly associated with the LMW adiponectin level than age, waist circumference or HDL-C. The results suggest that LMW adiponectin may be associated with episodes of asthma in males.

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