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Introduction This study evaluated the impact of a telephone support programme with telemonitoring on changes in healthy eating and active exercise in adults with prediabetes using the stage of change framework. Methods We performed a post hoc analysis using data from the Japan Diabetes Outcome Trial-1. A total of 2607 participants aged 20–65 years with impaired fasting glucose were recruited from the workplace/community in Japan and randomized to a one year telephone support programme intervention arm ( n = 1240) or self-directed control arm ( n = 1367). Participants in both arms received monthly data feedback from a weight scale and pedometer. The main outcome measure was the stages of change toward healthy eating and active exercise. The secondary outcome was fasting plasma glucose (FPG). Results After the one year intervention, the adjusted odds ratio of progressing to the action/maintenance stage in the intervention vs. control arm for healthy eating was 1.31 (95% confidence interval (CI) 1.21–1.43; p Discussion These findings suggest that the telephone support programme by healthcare providers advanced the stage of changes toward healthy eating in people with prediabetes. In particular, it decreased FPG levels in the contemplation stage.

Objectives Frequent self-weighing is associated with weight loss and maintenance, but the relationship between frequent self-weighing and the incidence of type 2 diabetes (T2D) remains unclear. The study aim was to examine the association between self-weighing frequency and the incidence of T2D in people with impaired fasting glucose (IFG). Results We tested the hypothesis that self-weighing frequency and the incidence of T2D are associated in 2607 people with IFG (1240 in the intervention arm; 1367 in the self-directed control arm). Both arms received a weighing scale with storage function. Healthcare providers offered a one-year goal-focused lifestyle intervention via phone. Participants were divided into 4 categories based on self-weighing frequency (No data sent [reference group], low: Trial registration This trial has been registered with the University Hospital Medical Information Network (UMIN000000662).

Objectives Using annual health check‐up data, the aim of this study was to identify target populations for lifestyle interventions to effectively prevent diabetes in a real‐world setting. Methods The Japan Diabetes Outcome Intervention Trial‐1, a prospective, cluster‐randomized controlled trial, was launched to test if year‐long telephone‐delivered lifestyle support by health professionals can prevent the development of type 2 diabetes (T2D) in people with impaired fasting glucose (IFG) identified at health check‐ups. A total of 2607 participants aged 20‐65 years with IFG were randomized to an intervention arm (n = 1240) or a control arm (n = 1367). We performed subgroup analysis to examine the effects of the intervention on the incidence of T2D in participants with body mass index (BMI) ≥25, metabolic syndrome (MetS), and non‐alcoholic or alcoholic elevated liver enzymes at the baseline. Cox regression analysis adjusted for sex was used to calculate the hazard ratios (HRs). Results In addition to IFG, the presence of BMI ≥25, MetS, and elevated liver enzymes increased the incidence of diabetes by two‐ or three‐fold. During a median follow‐up period of 4.9 years, only the non‐alcoholic elevated liver enzyme group showed a low incidence rate owing to lifestyle interventions (adjusted HR: 0.42, 95% confidence interval: 0.18‐0.98). Conclusion The results suggest that people who have IFG and non‐alcoholic elevated liver enzymes are a good target population for lifestyle interventions to effectively reduce the incidence of diabetes in a real‐world setting.

Background: Limited evidence is available about the relationship of lifestyle factors with glycated hemoglobin (HbA1c) in subjects with impaired glucose tolerance. The aim of study was to identify such determinant factors of HbA1c in subjects with impaired glucose tolerance. Methods: This cross-sectional study included 121 men and 124 women with impaired glucose tolerance, who were diagnosed based on a 75-g oral glucose tolerance test. Demographic and biochemical parameters, including the body mass index (BMI), fasting plasma glucose (FPG), 2-h post-load glucose (2-h PG), and HbA1c, were measured. The pancreatic β-cell function and insulin resistance were assessed using homeostasis model assessment (HOMA-β). Dietary intake was assessed by a food frequency questionnaire. Results: The levels of FPG, 2-h PG, and carbohydrate intake were correlated with the HbA1c level in men, while the FPG and 2-h PG levels were correlated with the HbA1c level in women. In multiple regression analyses, BMI, FPG, 2-h PG, and white rice intake were associated with HbA1c levels in men, while BMI, FPG, HOMA-β, and bread intake were associated with HbA1c levels in women. Conclusions: The present findings suggest that a substantial portion of HbA1c may be composed of not only glycemic but also several lifestyle factors in men with impaired glucose tolerance. These factors can be taken into consideration as modifiable determinants in assessing the HbA1c level for the diagnosis and therapeutic monitoring of the disease course. J Clin Med Res. 2017;9(4):360-365 doi: https://doi.org/10.14740/jocmr2928w

Background: Evidence of the long-term benefits of telephone-delivered lifestyle interventions is limited. This study investigated the ability of telephone-delivered lifestyle intervention ...

The beta-3 adrenergic receptor (ADRB3), primarily expressed in adipose tissue, is involved in the regulation of energy metabolism. The present study hypothesized that ADRB3 (Trp64Arg, rs4994) polymorphisms modulate the effects of lifestyle intervention on weight and metabolic parameters in patients with impaired glucose tolerance. Data were analyzed from 112 patients with impaired glucose tolerance in the Japan Diabetes Prevention Program, a lifestyle intervention trial, randomized to either an intensive lifestyle intervention group or usual care group. Changes in weight and metabolic parameters were measured after the 6-month intervention. The ADRB3 polymorphisms were determined using the polymerase chain reaction restriction fragment length polymorphism method. Non-carriers showed a greater weight reduction compared with the carriers in both the lifestyle intervention group and usual care group, and a greater increase of high-density lipoprotein cholesterol levels than the carriers only in the lifestyle intervention group. ADRB3 polymorphisms could influence the effects of lifestyle interventions on weight and lipid parameters in impaired glucose tolerance patients.

Objectives: Limited understanding of the causes of variability in individual response to similar lifestyle changes makes it challenging to design individualized diet plans for diabetes prevention. We previously reported a simulation model of lifestyle disease and tested it using data from DPP and a low carb-low fat diet crossover study. Here we used the model to analyze data from J-DOIT1 to understand the causes of variability and to optimize diet therapy. Methods: J-DOIT1 is a large-scale intervention study of 2,607 subjects with a 5.5 year follow-up. We selected 60 baseline-matched individuals from placebo and intervention arms. Model was calibrated to each subject’s body weight, FPG, HbA1c time courses to estimate physiology and lifestyle parameters (e.g., RMR, diet intake). Simulation analysis was used to optimize individual diet. Results: Individuals with the most and least improved biomarkers showed no significant difference in model-estimated energy balance or in self-reported lifestyle at baseline. Neither caloric deficit nor linear combinations of model-estimated parameters were predictive of outcomes, showing the value of our complex physiological model for prediction. The model suggests that unique sets of optimal diets exist for achieving individual health goals (Fig. 1). Fig. 1. Optimized changes in fat and carbohydrate intake for two individuals to reduce body weight by 5-7%. Fig. 1. Optimized changes in fat and carbohydrate intake for two individuals to reduce body weight by 5-7%. Disclosure J.H. Chen: None. M. Fukasawa: None. Q. Chen: None. S.P. Burns: None. K. Kumar: None. S. Nirengi: None. K. Takahashi: None. A. Suganuma: None. H. Kuzuya: None. N. Sakane: Research Support; Spouse/Partner; Pwc. G. Dwivedi: None.

Objective: The aim of this study was to evaluate the stages of change toward healthier behavior by telephone-delivery intervention in prediabetic individuals. Research Design and Methods: A total of 2607 participants aged 20-65 years with impaired fasting glucose were randomized to a one-year telephone-intervention intervention arm (n=1240) or a self-directed control arm with weighing scale and pedometer (n=1367). Stages of change were assessed using a self-administered questionnaire. Results: At the baseline, 5.9% were in the precontemplation stage, 50.6% were in the contemplation stage, and 25.5% were in the preparation stage in the change to healthy eating. At the baseline, 9.4% were in the precontemplation stage, 50.2% were in the contemplation stage, and 12.0% were in the preparation stage in the change toward adopting exercise habits. For participants who were in the precontemplation stage, the proportions of those progressing to the action/maintenance stage for a healthy eating after 1-year intervention and at the end of the trial were increased (17.5 and 16.1-percentage-point increase, respectively), but there was small increase for exercise habits (5.4 and 2.7-percentage-point increase, respectively). For participants who were in the precontenplation stage, the odds of progressing to the action/maintenance stage for the intervention vs. control arm for healthy eating after 1-year intervention and at the end of the trial were 3.07 (95% CI=1.23, 8.13) and 2.21 (95% CI=1.04, 4.67), respectively. The corresponding odds for excise habits were 1.59 (95% CI=0.70, 3.61) and 1.27 (95% CI=0.55, 2.91). The hazard ratio for the development of diabetes on receiving the intervention in the precontenplation stage of healthy eating at the baseline was 0.51. Conclusions: The intervention advanced the stages of changes toward healthy eating and might be effective for preventing diabetes even in the precontemplation stage. Disclosure N. Sakane: Research Support; Spouse/Partner; Pwc. S. Nirengi: None. K. Takahashi: None. A. Suganuma: None. K. Okazaki: Advisory Panel; Self; Eli Lilly and Company. Research Support; Self; Taisho Pharmaceutical Co., Ltd.. Speaker's Bureau; Self; Ono Pharmaceutical Co., Ltd., Mitsubishi Tanabe Pharma Corporation, Novo Nordisk A/S, Astellas Pharma US, Inc., Takeda Development Center Asia, Pte. Ltd., Terumo Medical Corporation, MSD K.K., Sanwa Kagaku Kenkyusho Co., Ltd.. Other Relationship; Self; Aichi prefecture government and Nagoya city government. K. Izumi: None. M. Noda: None. H. Kuzuya: None.

Objectives— Fish oil rich in n-3 polyunsaturated fatty acids (PUFAs) or n-3 PUFAs have been shown to reduce the incidence of coronary heart disease. Here we investigated the effect of highly purified eicosapentaenoic acid (EPA) on production of adiponectin, the only established antiatherogenic and antiinflammatory adipocytokine, in rodent models of obesity and human obese subjects. Methods and Results— We demonstrated that EPA increases adiponectin secretion in genetically obese ob/ob mice and high-fat diet–induced obese mice. In the in vitro coculture of adipocytes and macrophages, EPA reversed the coculture-induced decrease in adiponectin secretion at least in part through downregulation of tumor necrosis factor-α in macrophages. We also showed significant increase in plasma adiponectin concentrations in human obese subjects after a 3-month treatment with EPA (1.8 g daily). Multivariate regression analysis revealed that EPA treatment is the only independent determinant of plasma adiponectin concentrations. Conclusion— This study demonstrates that EPA increases adiponectin secretion in rodent models of obesity and human obese subjects, possibly through the improvement of the inflammatory changes in obese adipose tissue. Because EPA has reduced the risk of major coronary events in a large-scale, prospective, randomized clinical trial, this study provides important insight into its therapeutic implication in obesity-related metabolic sequelae.

Postprandial hyperglycemia and hyperlipidemia are considered risk factors for cardiovascular disease. This study was designed to elucidate whether improving the postprandial state by voglibose, an alpha-glucosidase inhibitor, leads to the reduction of oxidative stress markers and soluble adhesion molecules in obese type 2 diabetic patients. A total of 30 Japanese obese type 2 diabetic patients were randomly assigned and treated for 3 weeks with either diet alone (the control group) or diet plus voglibose (0.9 mg daily) (the voglibose group) (n=15 each). Analysis of the diurnal metabolic profiles revealed a significant reduction of postprandial hyperglycemia and hyperlipidemia in the voglibose group relative to the control group (P

The discriminating abilities of fasting plasma glucose (FPG) and HbA1c were compared on screening tests for impaired glucose tolerance (IGT) and IGT plus diabetes mellitus by the receiver operating characteristic (ROC) curve analysis. Furthermore, effects of sex, age and BMI were examined on sensitivity and specificity of the optimal cutoff points. This study included 997 subjects who were recruited for 75 g OGTT after the first screening of the Japan Diabetes Prevention Program. According to the 1997 criteria of the American Diabetes Association (ADA), 140 subjects were classified as diabetic and 256 as IGT. The areas under the ROC curves of FPG were significantly larger than those of HbA1c. The optimal cutoff points of FPG were 102 mg/dl for IGT and 105 mg/dl for IGT plus diabetes mellitus. Those of HbA1c were both 5.3%. In screening with FPG, females had significantly lower sensitivity and higher specificity than males, and the specificity for IGT plus diabetes mellitus was the lowest in the obese group. In screening with HbA1c, the specificity was low in the older and the obese groups. We concluded that FPG was superior to HbA1c for screening of IGT and IGT plus diabetes mellitus and the optimal cutoff point of FPG would be 102 mg/dl or greater.

Objective: This study analyzed the mutation of 21-hydroxylase deficiency (21-OHD) in 36 unrelated Japanese patients with congenital adrenal hyperplasia (CAH). Methods: All the exons of the functional CYP21 gene (CYP21A2) were analyzed by polymerase chain reaction (PCR) and PCR direct sequencing. Results: Apparent gene deletions and conversions were present in 23.6% of the 72 CAH alleles, in which the most frequent mutation was the IVS2-13 A/C>G (27.8%), followed by I172N (26.3%), consistent with the frequencies reported for other countries. Previously described mutations were not present in three unrelated cases. Sequence analysis of the complete functional CYP21A2 gene revealed three, not yet described mutations that represent a common pseudogene sequence. These three putative novel mutations are located in exon 1 (M1I), in exon 5 (1210–1211insT), and in exon 3 (R124H). Conclusions: In this study, we have identified three putative novel mutations. It remains to be determined whether these three mutations are responsible for the significant number of as yet uncharacterized CAH patients in Japan.

Enalapril is the most widely used angiotensin-converting enzyme (ACE) inhibitor in Japan, but few studies have examined its effect on insulin sensitivity in Japanese patients. Therefore, we used the glucose clamp technique to study the effects of enalapril on insulin sensitivity in nine patients with hypertension and type 2 diabetes mellitus (non—insulin-dependent diabetes mellitus [NIDDM]). Sixteen weeks after beginning treatment with enalapril, systolic and diastolic blood pressures had decreased significantly compared with baseline values; no significant changes were seen in glycemic control, body-mass index, or heart rate. During treatment, glucose infusion rates (M values) increased significantly, reflecting the degree of insulin sensitivity during the low insulinemic, hyperglycemic glucose clamp phase. In contrast, rates did not increase significantly during the high insulinemic, euglycemic glucose clamp phase. No significant changes in either insulin secretion or metabolic insulin clearance were observed. In addition, ACE activity significantly decreased throughout the glucose clamp procedure. Enalapril treatment did not have a significant effect on plasma angiotensin II concentrations across the glucose clamp; plasma bradykinin levels increased significantly, but only immediately before the clamp. The results of this study suggest that enalapril may affect insulin sensitivity through its effect on bradykinin levels rather than insulin secretion, thus improving glucose disposal.

The 14-3-3 protein family has been implicated in growth factor signaling. We investigated whether 14-3-3 protein is involved in insulin signaling in 3T3L1 adipocytes. A significant amount of insulin receptor substrate 1 (IRS-1) was immunodetected in the immunoprecipitate with anti-14-3-3beta antibody at the basal condition. 100 nM insulin increased the amount of IRS-1 in the immunoprecipitate 2.5-fold. The effect of insulin was abolished by 100 nM wortmannin. An in vitro binding study revealed that glutathione S-transferase-14-3-3beta fusion protein directly associates with recombinant IRS-1. Pretreatment of recombinant IRS-1 with alkaline phosphatase clearly decreased this association. Because the recombinant IRS-1 was not phosphorylated on its tyrosine residues, the results suggest that serine/threonine phosphorylation of IRS-1 is responsible for the association. When the cells are treated with insulin, phosphatidylinositol 3'-kinase (PI3K) is supposed to complex either 14-3-3beta-IRS-1 or IRS-1. The 14-3-3beta-IRS-1-PI3K and IRS-1-PI3K complexes were separately prepared by a sequential immunoprecipitation, first with anti-14-3-3beta and then with anti-IRS-1 antibodies. The specific activity of the PI3K in the former was approximately half of that in the latter, suggesting that 14-3-3beta protein bound to IRS-1 inhibits insulin-stimulated lipid kinase activity of PI3K in 3T3L1 adipocytes.

Mitogen-activated protein (MAP) kinase plays crucial roles in cell growth and differentiation. It has recently been shown that the MAP kinase cascade in growth factor signaling diverges and cross-talks with other signaling pathways. In the present study, we examined the effects of wortmannin, a specific inhibitor of phosphatidylinositol 3-kinase (PI3-kinase), on the activation of Ras, Raf-1 kinase, and MAP kinase by insulin and epidermal growth factor (EGF). The effect of LY294002, a structurally distinct PI3-kinase inhibitor, on the activation of Raf-1 kinase by both ligands was also examined. In 3T3-L1 adipocytes, 25 nmol/l wortmannin inhibited the insulin-induced activation of Raf-1 kinase to the basal level, whereas the same dose of wortmannin had little effect on the EGF-induced activation of Raf-1 kinase. One hundred μmol/1 LY294002 blocked insulin-induced activation of Raf-1 kinase without affecting EGF-induced activation of this kinase. Twenty-five nmol/l wortmannin inhibited the insulin-induced activation of MAP kinase to the basal level with no effect on the EGF-induced activation of this kinase. But the same dose of wortmannin did not affect the formation of guanosine 5′-triphosphate (GTP)-bound Ras stimulated by either ligand. In KB cells, results similar to those in 3T3-L1 adipocytes were obtained. In contrast, in Chinese hamster ovary cells overexpressing the human insulin receptor (CHO-HIR cells), neither wortmannin nor LY294002 inhibited the insulin-induced activation of Raf-1 kinase, and wort-mannin had little effect on the activation of MAP kinase by insulin. These results indicate that 1) PI3- kinase or wortmannin-sensitive molecules are involved in the interaction between activated Ras and Raf-1 kinase in the insulin signaling in 3T3-L1 adipocytes, 2) the involvement of PI3-kinase or wortmannin-sensitive molecules in the insulin-induced activation of MAP kinase appears to be cell-type specific, and 3) differential mechanisms to activate Raf-1 kinase and MAP kinase by insulin and EGF exist.

We investigated the effect of M16209 (1-(3-bromobenzo[b]furan-2-ylsulfonyl)hydantoin) on glucose transport and the insulin signaling system in mouse-derived 3T3-L1 adipocytes. When M16209 (30 and 100 microM) was added to 3T3-L1 adipocytes and preincubated for 24 hours, the uptake of 2-deoxy-D-[3H]-glucose (2-DG) after insulin stimulation was enhanced. This effect was seen when preincubation with M16209 was performed in the presence of 6 and 20 ng/ml insulin, but M16209 did not increase the response to 600 ng/ml insulin. M16209 (100 microM) did not interfere with (125)I-insulin binding or with tyrosine phosphorylation of the insulin receptor beta-subunit and IRS-1. M16209 (100 microM) also had no effect on the level of glucose transporter (GLUT1 and GLUT4) protein, but it promoted the translocation of intracellular GLUT4 to the plasma membrane. In contrast, M16209 had no effect on the translocation of GLUT1. In summary, M16209 enhanced 2-DG uptake by 3T3-L1 adipocytes. Insulin binding to its receptor, autophosphorylation of the insulin receptor beta-subunit, and tyrosine phosphorylation of IRS-1 were unaffected by M16209. However, translocation of GLUT4 from the intracellular pool to the plasma membrane was facilitated.

Background Lifestyle modifications are considered the most effective means of delaying or preventing the development of type 2 diabetes (T2DM). To contain the growing population of T2DM, it is critical to clarify effective and efficient settings for intervention and modalities for intervention delivery with a wide population reach. The Japan Diabetes Outcome Intervention Trial-1 (J-DOIT1) is a cluster randomized controlled trial to test whether goal-focused lifestyle coaching delivered by telephone can prevent the development of T2DM in high-risk individuals in a real-world setting. This paper describes the study design and recruitment of the study subjects. Methods For the recruitment of study subjects and their follow-up annually over 3 years, we employed health checkups conducted annually at communities and worksites. Health care divisions recruited from communities and companies across Japan formed groups as a cluster randomization unit. Candidates for the study, aged 20-65 years with fasting plasma glucose (FPG) of 5.6-6.9 mmol/l, were recruited from each group using health checkups results in 2006. Goal-focused lifestyle support is delivered by healthcare providers via telephone over a one-year period. Study subjects will be followed-up for three years by annual health checkups. Primary outcome is the development of diabetes defined as FPG≥7.0 mmol/l on annual health checkup or based on self-report, which is confirmed by referring to medical cards. Results Forty-three groups (clusters), formed from 17 health care divisions, were randomly assigned to an intervention arm (22 groups) or control arm (21 clusters) between March 2007 and February 2008. A total of 2840 participants, 1336 from the intervention and 1504 from the control arm, were recruited. Consent rate was about 20%, with no difference between the intervention and control arms. There were no differences in cluster size and characteristics of cluster between the groups. There were no differences in individual characteristics between the study arms. Conclusion We have launched J-DOIT1, a nation-wide trial to prevent the development of T2DM in high-risk individuals using telephone-delivered intervention. This trial is expected to contribute to evidence-based real-world preventive practices. Trial registration UMIN000000662.

Improvement of metabolic disorders by M16209 (1-(3-bromobenzofuran-2-ylsulfonyl)hydantoin), an antidiabetic agent, was studied in genetically obese Zucker fa/fa rats and C57BL/6J ob/ob mice. In fa/fa rats oral administration of M16209 (30 and 100 mg/kg/day) for 7 days dose dependently improved hyperinsulinemia without affecting body weight. Oral glucose loading (2 g glucose/kg body weight) after 10 days of administration to fa/fa rats revealed that M16209 significantly improved glucose tolerance both 30 and 60 min after glucose loading, but did not affect preload serum glucose levels. At one day after 13 days of administration of M16209, the serum levels of triglyceride, total cholesterol and free fatty acid were clearly lower in treated fa/fa rats than those in untreated rats. In C57BL/6J ob/ob mice, M16209 given for 28 days at doses of 30 and 100 mg/kg/day improved hyperinsulinemia, hyperglycemia and hypercholesterolemia without affecting body weight. In a hyperinsulinemic euglycemic clamp study in fa/fa rats, administration of M16209 for 7 days at a dose of 100 mg/kg/day significantly normalized the decreased metabolic clearance rate but did not show any effect on the augmented hepatic glucose output. These findings demonstrate that improvement of metabolic disorders in genetically obese rodents by M16209 is due to amelioration of insulin resistance in peripheral tissues.

Phosphoinositide 3-kinase (PI3-kinase) plays a crucial role in insulin signal transduction. We studied the molecular mechanism of the insulin-induced activation of PI3-kinase in rat hepatoma Fao cells using an antibody against the 110-kDa catalytic subunit (p110) and two against the 85-kDa regulatory subunit (p85 alpha). PI3-kinase activity increased 1.6-fold in anti-p85 immunoprecipitates after insulin stimulation, whereas it did not increase when cell lysates were first immunoprecipitated with anti-phosphotyrosine or anti-insulin receptor substrate-1 (IRS-1), then with anti-p85, suggesting that the PI3-kinase which associates with tyrosyl phosphoproteins including IRS-1 is responsible for the increase in kinase activity. The activated PI3-kinase molecules constituted 4-6% of the total PI3-kinase, and their specific activity was 11-14 times higher than that of the basal state. Anti-p110 recognized the catalytically active form of p110, and immunoprecipitated p110 only after exposure to insulin. Hence, the epitope of anti-p110, P200-C215, seems to be included in the portion of p110, the conformation of which is changed by insulin stimulation. We conclude that, in response to insulin stimulation, only a small fraction of p85 in the PI3-kinase pool associates with tyrosyl phosphoproteins including IRS-1, and that the specific activity of p110 is increased presumably through a conformational change including the P200-C215 region.

We have studied insulin-stimulated threonine phosphorylation of cellular proteins by immunoblotting and immunoprecipitation using antiphosphothreonine antibody (anti-P-Thr). A 50-kilodalton protein (p50) was found to be greatly phosphorylated on threonine residues upon insulin stimulation in intact rat hepatoma cells (Fao) and Chinese hamster ovary cells overexpressing human insulin receptor (CHO-HIR). Insulin induced threonine phosphorylation of this protein in a dose-dependent manner, with an ED50 of 3-6 x 10(-9) M. The 50-kilodalton phosphoprotein (pp50) was detectable 20 min after exposure of the cells to insulin, and phosphorylation reached a maximum after 90 min. Immunoprecipitation of pp50 with anti-P-Thr required extraction of the cellular proteins with sodium dodecyl sulfate and dithiothreitol, and subcellular fractionation of the cells revealed that pp50 is present in the membrane fraction, implying that pp50 is a protein integrated into the membrane component in the cells. Tryptic phosphopeptide mapping of the pp50 was distinct from that of the insulin receptor beta-subunit. Phosphoamino acid analysis of the pp50 demonstrated that insulin increased phosphorylation, mainly of threonine and moderately of serine, whereas pp50 did not contain phosphotyrosine. Cycloheximide, a protein synthesis inhibitor, did not affect the insulin-induced appearance of pp50 in the cells. pp50 was not detectable in A431 cells and KB cells stimulated by epidermal growth factor. These data suggest that p50 is a novel endogenous substrate for insulin-sensitive serine/threonine kinase in intact cells.

The present study was performed to assess the potential effectiveness of IGF-I as a blood glucose lowering agent in 10 patients with the syndromes of extremeinsulin resistance including type A syndrome, congenital generalized lipodystrophy and leprechaunism. With a twice daily subcutaneous injection of recombinant human IGF-I (0.06 to 0.4 mg/kg), fasting concentrations of total IGF-I increased about two- to fourfold over the values before treatment. IGF-I was effective in improving diabetic control; both fasting and postprandial plasma glucose concentrations fell with decreases in HbA1c and fructosamine values in the majority of the patients within the follow-up period ranging from 1 to 40 months. There was, however, one patientin whom painful neuropathy and proliferative retinopathy quickly developed after a rapid improvement of her glycemic control. Severe side effects were not reported in the other 9 patients.These results suggest that IGF-I could be used clinically as a hypoglycemic agent in diabetic patients with insulin resistance in whom insulin treatment is ineffective. However, because IGF-I stimulates cell growth in a variety of tissues, the potential unfavorable effects of IGF-I should also be monitored, particularly when IGF-I therapy is continued for a long period.

We treated a diabetic patient with familial multiple endocrine neoplasia type 1 (MEN 1) who had undergone total pancreatoduodenectomy. The patient received insulin and showed signs of symptomatic primary hyperparathyroidism (PHPT). The insulin requirement to control blood glucose before and after parathyroidectomy was compared by using an artificial pancreas. The insulin infusion rate during the day and at night was reduced to about one-third and half, respectively, after parathyroidectomy with autotransplantation of parathyroid tissues into the forearm. The daily insulin dose was reduced from 36 units to 14 units 2 weeks after surgery, and glycemic control showed further improvement 2 months after surgery with the same dose of insulin for up to 6 months. These observations suggest that insulin sensitivity increases after surgical correction of PHPT.

Background A randomized control trial was performed to test whether a lifestyle intervention program, carried out in a primary healthcare setting using existing resources, can reduce the incidence of type 2 diabetes in Japanese with impaired glucose tolerance (IGT). The results of 3 years' intervention are summarized. Methods Through health checkups in communities and workplaces, 304 middle-aged IGT subjects with a mean body mass index (BMI) of 24.5 kg/m2 were recruited and randomized to the intervention group or control group. The lifestyle intervention was carried out for 3 years by public health nurses using the curriculum and educational materials provided by the study group. Results After 1 year, the intervention had significantly improved body weight (-1.5 ± 0.7 vs. -0.7 ± 2.5 kg in the control; p = 0.023) and daily non-exercise leisure time energy expenditure (25 ± 113 vs. -3 ± 98 kcal; p = 0.045). Insulin sensitivity assessed by the Matsuda index was improved by the intervention during the 3 years. The 3-year cumulative incidence tended to be lower in the intervention group (14.8% vs.8.2%, log-rank test: p = 0.097). In a sub-analysis for the subjects with a BMI > 22.5 kg/m2, a significant reduction in the cumulative incidence was found (p = 0.027). Conclusions The present lifestyle intervention program using existing healthcare resources is beneficial in preventing diabetes in Japanese with IGT. This has important implications for primary healthcare-based diabetes prevention. Trial registration number UMIN000003136

We examined the effect of anti-phosphothreonine and anti-phosphoserine antibodies on insulin receptor autophosphorylation. These antibodies did not affect insulin binding activity of the receptor. These antibodies, however, inhibited insulin-stimulated autophosphorylation of insulin receptor, while did not affect EGF-stimulated autophosphorylation of EGF receptor. The inhibition was reversed by adding large amounts of phosphoserine or phosphothreonine. These data suggest that phosphoserine and phosphothreonine on insulin receptor play an important role in insulin-induced conformational change of the receptor.

We prepared antibodies against phosphoserine (P-Ser) and phosphothreonine (P-Thr) by immunizing rabbits with P-Ser or P-Thr conjugated to bovine serum albumin. The antibodies (anti-P-Ser and anti-P-Thr) were purified using P-Ser or P-Thr affinity columns. Anti-P-Thr was highly specific for P-Thr, while anti-P-Ser showed weak cross-reacitivity with P-Thr. We showed that these antibodies can immunodetect serine/threonine phosphorylated insulin and epidermal growth factor (EGF) receptors and several proteins which are phosphorylated on serine/threonine residues in response to insulin or EGF stimulation. The antibodies will certainly provide a good tool for discovering novel kinases and substrates involved in signal transduction.

Pregnancy is a rather rare event in acromegaly because fertility is often reduced during active disease. Previous reports of pregnancy in acromegalic patients showed that the pituitary growth hormone (GH) level was unaffected and the insulin-like growth factor (IGF)-1 level was elevated during the second and third trimesters. We describe here a case of persistent acromegaly that showed suppressed levels of GH and IGF-1 during pregnancy. The suppression of GH secretion and IGF-1 may be due to increased estrogen or other factors circulating in mid- to late pregnancy.

A high-fat (HF) diet causes insulin resistance. To characterize this type of insulin resistance, autophosphorylation of the insulin receptor (IR) in vitro and in vivo, phosphorylation of its endogenous substrates (pp190, pp175), and the amount of glucose transporters (GLUT-2, GLUT-4) were determined using muscles and liver from rats fed a HF-diet. Hyperinsulinemia and insulin resistance were observed by oral glucose tolerance test in the HF group. The levels of insulin binding to wheat germ agglutinin-purified insulin receptors from both muscles and liver were similar to those of the controls. Autophosphorylation of IR on tyrosine residues in vitro was decreased both in muscles and liver. Tyrosine-phosphorylation of both IR and an endogenous substrate (pp175) in response to insulin injection in vivo was decreased in the liver. However, a decrease in the phosphorylation of pp190 in muscles was not found. The levels of both GLUT-4 from muscles and GLUT-2 from liver in the crude membrane were comparable to those of the controls. These data suggest that insulin resistance in rats fed a HF-diet is a post-receptor defect in muscles, although tyrosine-phosphorylation of both IR and its endogenous substrate (pp175) were decreased in liver.

The present study was designed to see the effects of glucose on glucose transporter expression and glucose transport activity using cultured human skin fibroblasts. When the cells were incubated with various concentrations of glucose (11.1–44.4 mM), no differences were found in the HepG2 glucose transporter mRNA, protein levels and basal and insulin-stimulated 2-deoxyglucose uptake. Glucose deprivation, however, resulted in approximately 4-fold increases in the mRNA and 3-fold increases in the protein and the basal 2-deoxyglucose uptake. Chronic exposure to insulin increased the glucose transporter protein levels to similar degrees in the cells incubated with 11.1, 22.2 and 44.4 mM glucose accompanied by increases in the glucose transport activity. Effects of insulin on the glucose transporter mRNA and protein levels, however, were not evident in the glucose-deprived cells. It is concluded that glucose transport activity correlates closely with HepG2 glucose transporter expression in cultured human fibroblasts and that glucose (11.1–44.4 mM) does not affect the glucose transporter expression and glucose transport activity.

Background Small dense low-density lipoprotein (sd-LDL) is an atherogenic lipoprotein closely associated with an increased risk of cardiovascular diseases. However, a precise analysis of the actual amount of sd-LDL-cholesterol (sd-LDL-C) in patients with metabolic syndrome (MS) has not been performed. Methods and results Among 214 patients enrolled in the present study, 101 patients (47%) met the Japanese MS criteria. The serum levels of sd-LDL-C determined with a dual detection HPLC system were higher in MS than non-MS patients, while total cholesterol and low-density lipoprotein-cholesterol (LDL-C) were similar between MS and non-MS patients. Compared with the sd-LDL-C and LDL-C level, the ratio sd-LDL-C/LDL-C was more closely correlated with various parameters associated with MS. A multivariate regression analysis revealed that the ratio sd-LDL-C/LDL-C is the strongest independent determinant of hypoadiponectinemia. Furthermore, weight reduction therapy through diet and exercise rapidly decreased LDL-C but slowly decreased sd-LDL-C. At 12 months after the therapy, weight reduction led to a significant decrease in the ratio sd-LDL-C/LDL-C in tandem with increasing adiponectin levels. Conclusions These findings demonstrate that the ratio sd-LDL-C/LDL-C is tightly connected with hypoadiponectinemia and provides a useful clinical indicator for MS. The results also suggest that the elevation of this ratio can be modulated by long-term lifestyle changes.

The Japan Diabetes Society (JDS) conducted a multicenter study on the immunogenetics of early-onset insulin-dependent diabetes mellitus (IDDM) of the Japanese. Human leukocyte antigen (HLA), properdin factor B (BF), immunoglobulin heavy-chain complex (Gm), and glyoxalase of erythrocytes (GLO) were typed, and organ-specific autoantibodies, including islet cell antibody (ICA), were assayed in 159 Japanese IDDM patients and their family members and in 258 healthy Japanese controls. The HLA-DRw9 phenotype and HLA-Bw61/DRw9 haplotype were significantly increased among the patients with autoantibodies other than ICA but with no autoimmune diseases (RR = 5.84, cP less than 0.001; and RR = 7.45, P less than 0.001), whereas the HLA-DR4 phenotype and HLA-Bw54/DR4 haplotype were significantly increased in those without either the autoantibodies or autoimmune diseases (RR = 2.64, cP less than 0.001; and RR = 4.55, P less than 0.001). The HLA-DR4 phenotype was significantly increased in the patients with autoimmune thyroid diseases (RR = 6.21, cP less than 0.05). In all groups of patients, the HLA-DR2 phenotype was significantly decreased, and the relative risk of the HLA-DRw9/DR4 genotype was highest among all HLA-DR genotypes. No significant association was found between HLA type and the duration or incidence of ICA. Gm types of g and gft were significantly increased in the patients with the autoantibodies (RR = 2.11, P less than 0.05; and RR = 34.11, P less than 0.05), whereas the BF-F phenotype was significantly decreased in the patients either with or without autoantibodies (RR = 0.43, P less than 0.05; and RR = 0.46, P less than 0.05). There was no association between IDDM and GLO type. These data indicate that immunogenetic bases underlying IDDM of the Japanese are heterogeneous, as are those in Caucasians.

Objectives To examine the effects of telephone-delivered lifestyle coaching on preventing the development of type 2 diabetes mellitus (T2DM) in participants with impaired fasting glucose (IFG). Design Cluster randomised trial. Setting 40 groups from 17 healthcare divisions in Japan: companies (31), communities (6) and mixed settings (3). Participants Participants aged 20–65 years with fasting plasma glucose (FPG) of 5.6–6.9 mmol/L were invited from the 17 healthcare divisions. Randomisation The groups were then randomly assigned to an intervention or a control arm by independent statisticians according to a computer-generated list. Intervention The intervention arm received a 1-year telephone-delivered intervention provided by three private lifestyle support centres (at different frequencies: low-frequency (3 times), middle-frequency (6 times) and high-frequency (10 times) support calls). The intervention and control arms both received self-help devices such as a weight scale and pedometer. Outcomes Participants were followed up using data from annual health check-ups and a questionnaire regarding lifestyle. The primary outcome was the development of T2DM defined as FPG ≥7.0 mmol/L, the diagnosis of diabetes, or use of an antidiabetic drug, confirmed by referring to medical cards. Results Of 14 473 screened individuals, participants were enrolled in either the intervention (n=1240) arm or control (n=1367) arm. Overall, the HR for the development of T2DM in the intervention arm during 5.5 years was 1.00 (95% CI 0.74 to 1.34). In the subanalysis, the HR was 0.59 (95% CI 0.42 to 0.83) in the subgroup that received phone calls the most frequently, compared with the control arm. A limitation of the study includes a lack of blinding. Conclusions High-frequency telephone-delivered lifestyle support could effectively prevent T2DM in participants with IFG in a primary healthcare setting, although low-frequency and middle-frequency phone calls did not. Trial registration number This trial has been registered with the University Hospital Medical Information Network (UMIN000000662).

Eicosapentaenoic acid (EPA), one representative of n-3 unsaturated fatty acids (n-3 PUFAs), is clinically used for its lipid-lowering effects (1). n-3 PUFAs were shown to exert various physiological functions such as antiplatelet actions (by antagonizing effects of arachidonic acid) and plaque stabilization (2,3). Several epidemiological studies have explored antiatherogenic and cardioprotective effects of n-3 PUFA that are abundantly contained in fish oil (4). Dyslipidemia accompanying the metabolic syndrome is often associated with elevated levels of remnant lipoprotein particles and small dense LDL (sdLDL), which are newly recognized risk factors for cardiovascular disease (CVD) (5). It was reported that fish oil improved lipoprotein subclass profiles in subjects with an atherogenic lipoprotein phenotype (6). Besides EPA, docosahexaenoic acid and cholesterol are present in fish oil (7), but it is not clear whether purified EPA independently affects lipoprotein subclass profiles. Therefore, we used purified EPA ethyl ester and examined effects of EPA on atherogenic sdLDL particles and remnant lipoprotein particles in the metabolic syndrome, a precursor of CVD. Furthermore, sdLDL has been reported to synergistically interact with inflammation in pathophysiologic processes leading to CVD (8). Therefore, we simultaneously measured effects of EPA on C-reactive protein (CRP), a marker of inflammation, and examined how alteration of lipoprotein profiles by EPA affects systemic inflammation. A total of 44 Japanese obese type 2 diabetic patients were recruited in our clinics (Table 1). All patients satisfied the definition and diagnostic criteria of the metabolic syndrome proposed by the National Metabolic Syndrome Criteria Study Group of Japan in 2005 (9). Accordingly, an individual is diagnosed with metabolic syndrome if he or she has central adiposity plus two or more of the following three factors: 1 ) raised concentration of triglycerides …

Obesity promotes the progression of atherosclerosis by inducing multiple cardiovascular and metabolic derangements such as diabetes, hypertension, and dyslipidemia, all of which have high atherogenic potential. Adipose tissue has been considered an important endocrine organ that secretes many biologically active substances, collectively known as adipocytokines (1). Two major adipocytokines, leptin and adiponectin, are thought to play important roles in the regulation of cardiovascular and metabolic homeostasis. Leptin acts directly on the hypothalamus, thereby regulating food intake and energy expenditure (2). Plasma leptin concentrations are significantly elevated in obese subjects in proportion to the degree of adiposity (3), suggesting that hyperleptinemia may play a role in the pathogenesis of obesity-related complications. On the other hand, adiponectin increases tissue fat oxidation, leading to reduced levels of fatty acids and tissue triglyceride content, thus increasing insulin sensitivity (4). Paradoxically, plasma adiponectin concentrations are decreased in obese subjects (5), suggesting that hypoadiponectinemia is involved in the pathophysiology of obesity. Two recent studies have demonstrated that vascular remodeling and neointimal formation are markedly attenuated in leptin-deficient ob/ob mice and db/db mice with leptin receptor mutation (6,7), suggesting that leptin may accelerate the development of vascular injury. Conversely, studies with adiponectin-deficient mice have revealed that adiponectin plays a protective role in the development of atherosclerosis (8,9). In obese type 2 diabetic patients who are susceptible to atherosclerosis, plasma concentrations of leptin are increased, whereas those of adiponectin …

The metabolic syndrome is featured by obesity, dyslipidemia and insulin resistance, additionally associated with inflammatory and fibrinolytic dysfunctions, all of which are risk factors of cardiovascular diseases and type 2 diabetes. The lifestyle factors that could cause and aggravate the metabolic syndrome are physical inactivity, calorie-dense diet, habitual alcohol drinking and smoking, and psychosocial stress. Energy excess along with a lot of saturated fat, i.e. more fast food and sugar-containing drinks, and sedentary lifestyle like television viewing are contributing to the epidemic of obesity. The significance of lifestyle from birth to adulthood will be reviewed in the context of the metabolic syndrome, as well as the background and environment in which the convenient lifestyle spread far and wide among us.

To study the role of adiponectin, a novel adipocyte-specific secreted protein, on the pathophysiology of eating disorders, circulating levels of fasting adiponectin, leptin, insulin, and glucose were measured in 31 female patients with anorexia nervosa (AN) and in 11 with bulimia nervosa. Hormone levels were compared with 16 age-matched, normal body weight controls, six healthy constitutionally thin subjects, and nine obese subjects. Moreover, changes in levels were reevaluated after nutritional treatment and weight gain in 13 patients with AN. Serum adiponectin concentrations in AN and bulimia nervosa were significantly lower than those in normal-weight controls. These results were unexpected because the levels were high in constitutionally thin subjects and low in obese subjects, which provide a negative correlation with body mass index (BMI) and body fat mass. In contrast, serum leptin levels correlated very well with BMI and fat mass among all the patients and controls. The insulin resistance was significantly low in AN and high in obese subjects. The concentrations of adiponectin after weight recovery increased to the normal level despite a relatively small increase in BMI. These findings suggest that abnormal feeding behavior in the patients with eating disorders may reduce circulating adiponectin level, and weight recovery can restore it.

Some plant compounds or herb mixtures are popular alternatives to conventional therapies and contain organic compounds that bind to some nuclear receptors, such as the estrogen receptor (ER), to exert various biological effects. We studied the effect of various herbal extracts on ERalpha and ERbeta isoforms. One herbal extract, Rhei rhizoma (rhubarb), acts as an agonist to both ERalpha and ERbeta. The phytochemical lindleyin, a major component of rhubarb, might contribute to this estrogenic activity through ERalpha and ERbeta. 4-Hydroxytamoxifen, an ER antagonist, completely reversed the estrogenic activity of lindleyin. Lindleyin binds to ERalpha in vitro, as demonstrated using a fluorescent polarization assay. The in vivo effect of rhubarb extract was studied using a vitellogenin assay system in the freshwater fish, Japanese medaka (Oryzias latipes). There were marked increases in serum vitellogenin levels in male medaka exposed to rhubarb extract. We conclude that lindleyin, a component of some herbal medicines, is a novel phytoestrogen and might trigger many of the biological responses evoked by the physiological estrogens.

Bisphenol A (BPA), a monomer of polycarbonate plastics, has been shown to possess estrogenic properties and act as an agonist for the estrogen receptors. Although an epidemiologically based investigation has suggested that some chemicals could disrupt thyroid function in animals, the effects on thyroid hormone receptors (TRs) are unknown. We show here that BPA inhibits TR-mediated transcription by acting as an antagonist. In the transient gene expression experiments, BPA suppressed transcriptional activity that is stimulated by thyroid hormone (T3) in a dose-dependent manner. The inhibitory effects were observed in the presence of physiological concentrations of T3. In contrast, in the case of negatively regulated TSHα promoter, BPA activated the gene transcription that is suppressed by T3. To elucidate possible mechanisms of the antagonistic action of BPA, the effects on T3 binding and cofactor interaction with TR were examined. The Ki value for BPA was 200 μm when assessed by inhibition of [125I]T3 binding to rat hepatic nuclear TRs. In a mammalian two-hybrid assay, BPA recruited the nuclear corepressor to the TR. These results suggest that BPA could displace T3 from the TR and recruit a transcriptional repressor, resulting in gene suppression. This is the first report that BPA can antagonize T3 action at the transcriptional level. BPA may disrupt the function of various types of nuclear hormone receptors and their cofactors to disturb our internal hormonal environment.

Objectives To determine the effects of a lifestyle intervention on the development of type 2 diabetes mellitus (T2DM) among participants with impaired glucose tolerance (IGT), in particular in the subgroup with baseline glycated hemoglobin (HbA1c) levels ≥5.7%, in primary healthcare settings. Design Randomized controlled trial. Setting 32 healthcare centers in Japan. Participants Participants with IGT, aged 30–60 years, were randomly assigned to either an intensive lifestyle intervention group (ILG) or a usual care group (UCG). Interventions During the initial 6 months, participants in the ILG received four group sessions on healthy lifestyles by public health providers. An individual session was further conducted biannually during the 3 years. Participants in the UCG received usual care such as one group session on healthy lifestyles. Outcome measures The primary endpoint was the development of T2DM based on an oral glucose tolerance test. Results The mean follow-up period was 2.3 years. The annual incidence of T2DM were 2.7 and 5.1/100 person-years of follow-up in the ILG (n=145) and UCG (n=149), respectively. The cumulative incidence of T2DM was significantly lower in the ILG than in the UCG among participants with HbA1c levels ≥5.7% (log-rank=3.52, p=0.06; Breslow=4.05, p=0.04; Tarone-Ware=3.79, p=0.05), while this was not found among participants with HbA1c levels Conclusions Intensive lifestyle intervention in primary healthcare setting is effective in preventing the development of T2DM in IGT participants with HbA1c levels ≥5.7%, relative to those with HbA1c levels Trial registration number UMIN000003136.

Leptin is an adipocyte-derived circulating satiety factor with a variety of biological effects. Evidence has accumulated suggesting that leptin may modulate glucose and lipid metabolism. In the present study, we examined lipid metabolism in transgenic skinny mice with elevated plasma leptin concentrations. The plasma concentrations of triglycerides and free fatty acids in transgenic skinny mice were 71.5 ( P < 0.01) and 89.1% ( P < 0.05) of those in their nontransgenic littermates, respectively. Separation of plasma into lipoprotein classes by ultracentrifugation revealed that very low density lipoprotein-triglyceride concentrations were markedly reduced in transgenic skinny mice relative to the controls. The clearance of triglycerides estimated by a fat-loading test was enhanced in transgenic skinny mice; the triglyceride concentration in transgenic skinny mice 3 h after fat loading was 39.7% ( P < 0.05) of that of their nontransgenic littermates. Postheparin plasma lipoprotein lipase activity increased 1.4-fold ( P < 0.05) in transgenic skinny mice. Our data demonstrated a significant reduction in plasma triglyceride concentrations, accompanied by increased lipoprotein lipase activity in transgenic skinny mice overexpressing leptin, suggesting that leptin plays a role in long-term triglyceride metabolism.

It has been shown that an adenine (A) to guanine (G) transition at position 3243 of the mitochondrial transfer RNA(tRNA)leu(UUR) gene is associated with a subgroup of diabetes mellitus. Therefore, we screened for this transition in 86 patients with non-insulin-dependent diabetes mellitus (NIDDM) in which two or three generations were affected with diabetes, in 14 patients with insulin-dependent diabetes mellitus, and in 9 families with diabetes mellitus and/or associated disorders suggesting mitochondrial gene abnormalities. We failed to identify the mutation in 100 diabetic patients, 86 NIDDM and 14 insulin-dependent diabetes mellitus (IDDM). Out of the latter 9 families, we identified an A to G transition in 14 individuals in 5 families. Diabetes mellitus was shown to be maternally inherited in one family. In 9 of 14 patients with the mutation, insulin was required to treat diabetes mellitus, indicating impaired insulin secretion. A hyperglycemic clamp test performed in one subject revealed significant impairment of insulin secretion, whereas euglycemic clamp test showed normal insulin sensitivity in this patient. The heteroplasmy of the mutant mitochondrial DNA (mtDNA) in leukocytes does not appear to correlate with the severity of diabetes in terms of the insulin therapy required. Body mass index of the affected individuals was less than 23.3. In one family, in addition to diabetes mellitus and hearing loss, hypoparathyroidism was associated with the mutation, suggesting that hypoparathyroidism is caused by the impaired processing and/or secretion of proparathyroid hormone due to the mutation. In addition, the affected subjects presented with proteinuria at the time of diagnosis of diabetes mellitus which appeared not to be related with diabetic nephropathy.(Internal Medicine 37: 265-272, 1998)

A 56-year-old Japanese man presented with a 2-month duration of polyuria and polydipsia. The diagnosis of diabetes insipidus was confirmed by water deprivation and vasopressin injection. The secretory function of the adenohypophysis was estimated as normal by a variety of provocative tests. Magnetic resonance imaging (MRI) displayed the loss of the hyperintense signal of the neurohypophysis and a tumor-like lesion confined to the neurohypophysis. The tissue specimen resected at transsphenoidal surgery showed diffuse lymphocytic infiltration. These findings suggest that this is a candidate case for lymphocytic infundibuloneurohypophysitis (LIN) that is not identical to classical lymphocytic hypophysitis. This patient will be followed up to determine whether this case simply represents an early stage of classical hypophysitis or a different clinical entity.

Leptin, a recently identified hormone, is believed to reduce appetite and maintain body weight. The mRNA of leptin is expressed only in mature adipose cells. To clarify the regulation of leptin gene expression in adipocytes, 3T3-L1 adipocytes were treated for 16 h with various agents known to modulate lipid metabolism, and then the leptin mRNA was measured by the reverse transcription-polymerase chain reaction method. Interestingly, both norepinephrine and isoproterenol reduced the level of leptin mRNA to about 20% of that found in untreated control cells in a dose-dependent fashion. The maximum reduction occurred at 100 nmol/l of either norepinephrine or isoproterenol, and the half-maximal effect was observed at approximately 3 nmol/l norepinephrine and approximately 1 nmol/l isoproterenol. Propranolol reversed about 50% of the reduction by either norepinephrine or isoproterenol. In contrast, phentolamine did not inhibit the reduction by either norepinephrine or isoproterenol. Moreover, both cholera toxin and dibutyryl cAMP decreased the level of leptin mRNA to about 10% of that in control cells in a dose-dependent fashion. The maximum effect was elicited at 100 ng/ml cholera toxin and 100 micromol/l dibutyryl cAMP. The concentration producing the half-maximal effect was approximately 1 ng/ml cholera toxin and approximately 50 micromol/l dibutyryl cAMP. Dibutyryl cGMP, however, did not affect leptin gene expression. These results suggest that a signaling pathway that results in the activation of protein kinase A regulates leptin gene expression in 3T3-L1 adipocytes.

The effects of M16209 (1-(3-bromobenzo[b]furan-2-ylsulfonyl)hydantoin) on the in vivo insulin sensitivity of rats were studied by euglycemic clamp methods after 1 week of administration (10 or 100 mg/kg/d). M16209 increased both the glucose infusion rate (GIR) and metabolic clearance rate (MCR) of 3-[3H]- glucose, but did not suppress hepatic glucose output. M16209 also increased the [3H]-2-deoxyglucose utilization rate, rate of incorporation of [14C]-glucose into glycogen, and glycolytic flux in the soleus and red gastrocnemius muscles, but not in the extensor digitorum lungus and white gastrocnemius muscles. M16209 affected neither the [3H]-2-deoxyglucose utilization rate nor the rate of incorporation of [14C]-glucose into lipids in epididymal adipose tissue. In the soleus muscle, M16209 decreased glucose-6-phosphate (G6P) and fructose-6-phosphate (F6P) content, but did not affect fructose-1,6-bisphosphate (F-1,6-BP) content. Moreover, M16209 increased glycogen synthase-I activity and fructose-2,6-bisphosphate (F-2,6-BP) content in the soleus muscle. These results suggest that M16209 increases insulin-stimulated glucose uptake in peripheral tissues, particularly oxidative muscles, through potentiation of insulin action on glycogen synthesis and glycolysis. Glycogen synthase and phosphofructokinase (PFK) appear to be major targets of the action of M16209.

The Japan Diabetes Society (JDS) conducted a multicenter study on the immunogenetics of insulin-dependent diabetes mellitus (IDDM) among Japanese. The previous report of the JDS study described HLA types and other immunogenetic markers in Japanese patients with IDDM. In the present report, the autoimmunity of Japanese patients was studied by measuring ICA and other organ-specific autoantibodies in patients with different durations of IDDM. The prevalences of ICA were the highest in the first year after diagnosis (73.1%) and decreased to 58.0%, 18.3% and 2.8% in 1–5 years, 5–10 years and 10 years or more after diagnosis, respectively (P < 0.01), while the prevalences of the other organ specific autoantibodies increased gradually with duration of IDDM from 20% in the first year to 35% in 10 years or more after diagnosis (P < 0.05). There were no sex differences in the prevalences of ICA but those of other organ-specific autoantibodies were significantly higher in female patients than in male patients (P < 0.01). The prevalence of ICA was not correlated with sex, age at onset or HLA types. In one of the subjects, a girl, the titers of ICA increased in parallel with a decrease in insulin secretion before the development of overt IDDM and declined thereafter. These findings suggest that IDDM might develop when the autoimmunity specific to pancreatic islets is triggered in people with underlying autoimmunity as shown by the presence of organ-specific autoantibodies other than ICA.

Changes in insulin-stimulated glucose metabolism were studied in young and aged subjects, subjects with impaired glucose tolerance, and patients with NIDDM by means of the glucose clamp technique. The diabetic group includes obese and non-obese patients treated without insulin and non-obese patients treated with insulin. The glucose disposal rate (GDR) was decreased in aged subjects (5.8 +/- 0.4 mg/kg/min) compared with young controls (7.4 +/- 0.3 mg/kg/min). In patients with IGT, it was further decreased to 3.6 +/- 0.5 mg/kg/min, which was comparable to the rate in NIDDM without insulin treatment (3.3 +/- 0.4 mg/kg/min). There were no differences in the GDR between obese (3.0 +/- 0.3 mg/kg/min) and non-obese (3.4 +/- 0.6 mg/kg/min) diabetic patients. In insulin-treated diabetic patients, GDR ranged widely, but the mean value was partially normalized (5.2 +/- 0.9 mg/kg/min). In the diabetic group, no correlation was observed between fasting blood glucose and GDR. These results suggest that in the course of developing NIDDM, a decrease in insulin-stimulated glucose uptake precedes a rise in fasting blood glucose. Thus, as previously reported for Caucasian NIDDM patients, resistance to insulin-stimulated glucose uptake may be one of the basic defects in Japanese patients with NIDDM. The degree of glycemia, however, is not directly related to the magnitude of the defect in insulin action.