Decreases in serum testosterone concentrations in aging men are associated with metabolic disorders. Testosterone has been reported to increase GLUT4-dependent glucose uptake in skeletal muscle cells and cardiomyocytes. However, studies on glucose uptake occurring in response to testosterone stimulation in adipocytes are currently not available. This study was designed to determine the effects of testosterone on glucose uptake in adipocytes. Glucose uptake was assessed with 2-[(3)H] deoxyglucose in 3T3-L1 adipocytes. GLUT4 translocation was evaluated in plasma membrane (PM) sheets and PM fractions by immunofluorescence and immunoblotting, respectively. Activation of GLUT4 translocation-related protein kinases, including Akt, AMPK, LKB1, CaMKI, CaMKII, and Cbl was followed by immunoblotting. Expression levels of androgen receptor (AR) mRNA and AR translocation to the PM were assessed by real-time RT-PCR and immunoblotting, respectively. The results showed that both high-dose (100 nM) testosterone and testosterone-BSA increased glucose uptake and GLUT4 translocation to the PM, independently of the intracellular AR. Testosterone and testosterone-BSA stimulated the phosphorylation of AMPK, LKB1, and CaMKII. The knockdown of LKB1 by siRNA attenuated testosterone- and testosterone-BSA-stimulated AMPK phosphorylation and glucose uptake. These results indicate that high-dose testosterone and testosterone-BSA increase GLUT4-dependent glucose uptake in 3T3-L1 adipocytes by inducing the LKB1/AMPK signaling pathway.

Recent studies have suggested that the inter-arm blood pressure difference (IAD) is associated with cardiovascular events and mortality. The aim of this study was to assess whether the IAD could be a marker for subclinical atherosclerosis in patients with type 2 diabetes who are at high risk of cardiovascular disease (CVD). In a cross-sectional retrospective study of 206 Japanese patients with type 2 diabetes aged 49-76 years, we examined the correlation of the IAD with the carotid intima-media thickness (IMT), ankle-brachial index (ABI) or cardio ankle vascular index (CAVI). The IAD was positively correlated with the maximum IMT (r=0.266, P<0.0001), mean IMT (r=0.209, P=0.00726) or CAVI (r=0.240, P=0.0005). The IAD was higher in patients with CVD than in those without (P=0.0020). A multiple linear regression analysis demonstrated that the IAD was an independent determinant of maximum IMT (β=0.169, P=0.0167), mean IMT (β=0.178, P=0.0153), ABI (β=-0.222, P=0.0033) or CAVI (β=0.213, P=0.0011) after adjusting for known risk factors. The area under the receiver operating characteristic curve (AUC) of the IAD as a predictor of subclinical atherosclerosis was similar to the AUC of the Framingham 10-year coronary heart disease risk score. In conclusion, the IAD could be a novel risk marker for subclinical atherosclerosis in patients with type 2 diabetes.

We investigated the impact of combined effect of body mass index and waist-to-height ratio on risk of diabetes. Overweight and abdominal obesity were defined as body mass index ≥23 kg/m2 and waist-to-height ratio ≥0.5, respectively. We divided participants into four groups according to presence of overweight and/or abdominal obesity. About 20% individuals with overweight did not complicated with an abdominal obesity. Among 3,737 participants, 286 participants had diabetes at baseline-examination. Adjusted odds ratios for prevalence of diabetes compared with non-overweight participants without abdominal obesity were as follow: 1.87 (95% confidence interval 1.09–3.14, p = 0.024) in non-overweight participants with abdominal obesity, 1.51 (0.87–2.55, p = 0.141) in overweight participants without abdominal obesity and 3.25 (2.37–4.52, p<0.001) in overweight participants with abdominal obesity. In the follow-up examination, 86 participants were diagnosed as diabetes among 2,263 participants. Adjusted odds ratios for incident diabetes were as follow: 2.59 (0.98–6.44, p = 0.056) in non-overweight participants with abdominal obesity, 1.65 (0.64–4.00, p = 0.288) in overweight participants without abdominal obesity and 2.77 (1.55–5.15, p<0.001) in overweight participants with abdominal obesity. Non-overweight individuals with abdominal obesity as well as overweight individuals with abdominal obesity was associated with diabetes compared with non-overweight individuals without abdominal obesity.

BackgroundHemoglobin A1c is the main treatment target for patients with type 2 diabetes. It has also been shown recently that postprandial glucose and daily glucose fluctuations affect the progression of diabetic complications and atherosclerotic damages.MethodsContinuous glucose monitoring was performed in patients with type 2 diabetes to evaluate the efficacy of repaglinide vs. glimepiride on postprandial glucose spikes and fluctuations. A total of 10 Japanese patients with type 2 diabetes treated with glimepiride monotherapy were enrolled. After observation period for 8 weeks, glimepiride was changed to repaglinide. Continuous glucose monitoring was performed whilst consuming calorie-restricted diets for two days at baseline and at the end of the 12-week trial. Blood and urine samples were collected for measurement of glucose control parameters and inflammatory and oxidative stress markers on the last day of taking either glimepiride or repaglinide.ResultsNine patients completed the trial. Although the glucose control parameters were not significantly different between glimepiride and repaglinide, the mean amplitude of glycemic excursions measured by continuous glucose monitoring was significantly reduced by changing treatment from glimepiride to repaglinide. The levels of plasminogen activator inhibitor-1, high sensitivity C-reactive protein, and urinary 8-hydoroxydeoxyguanosine were reduced significantly by repaglinide treatment.ConclusionThese results suggest that repaglinide may decrease the risk of cardiovascular disease in type 2 diabetes by minimizing glucose fluctuations thereby reducing inflammation and oxidative stress.

Transient remission of NAFLD significantly decreased the risk of developing T2DM.