Insulin

About: Insulin is a research topic. Over the lifetime, 124295 publications have been published within this topic receiving 5129734 citations. The topic is also known as: human insulin.

Mechanism by which high-dose aspirin improves glucose metabolism in type 2 diabetes

Abstract: Recent studies have implicated fatty acid-dependent activation of the serine kinase IKKbeta, which plays a key role in tissue inflammation, in the pathogenesis of insulin resistance. High doses of salicylates have recently been shown to inhibit IKKbeta activity and might therefore ameliorate insulin resistance and improve glucose tolerance in patients with type 2 diabetes. To test this hypothesis, we studied nine type 2 diabetic subjects before and after 2 weeks of treatment with aspirin ( approximately 7 g/d). Subjects underwent mixed-meal tolerance tests and hyperinsulinemic-euglycemic clamps with [6,6-(2)H2]glucose to assess glucose turnover before and after treatment. High-dose aspirin treatment resulted in a approximately 25% reduction in fasting plasma glucose, associated with a approximately 15% reduction in total cholesterol and C-reactive protein, a approximately 50% reduction in triglycerides, and a approximately 30% reduction in insulin clearance, despite no change in body weight. During a mixed-meal tolerance test, the areas under the curve for plasma glucose and fatty acid levels decreased by approximately 20% and approximately 50%, respectively. Aspirin treatment also resulted in a approximately 20% reduction in basal rates of hepatic glucose production and a approximately 20% improvement in insulin-stimulated peripheral glucose uptake under matched plasma insulin concentrations during the clamp. In conclusion, these data support the hypothesis that IKKbeta represents a new target for treating type 2 diabetes mellitus.

Reduced beta-cell mass and expression of oxidative stress-related DNA damage in the islet of Japanese Type II diabetic patients.

Abstract: We examined the pancreatic islet lesions in Japanese patients with Type II diabetes mellitus to determine if the damage was related to oxidative stress. Morphometric analyses were performed on immunostained sections of the tail portion of the pancreas from 14 diabetic and 15 non-diabetic patients. Amyloid deposition and oxidative stress-induced tissue damage were evaluated by Congo-red staining and immunostaining. Resistance to oxidative stress was assessed from immunostaining results for Cu, Zn-superoxide dismutase (SOD). Expression of (pro)insulin mRNA was assessed by in situ hybridisation. The pancreas from diabetic patients had amyloid deposition in about 15 % of the islets, intensified reactions of 8-OHdG and HNE, as well as reduced expression of SOD. Islet volume density of beta cells and total beta-cell mass in the pancreas from diabetic patients were reduced by 22 % (p < 0.001) and 30 % (p < 0.05). Islet volume density and total mass of (pro)insulin mRNA-positive cells were similarly reduced in diabetic patients by 22 % (p < 0.001) and 39 % (p < 0.05), respectively. Islet volume density of A cells was increased by 20 % (p < 0.001) but total mass did not change. There were no changes in volume densities of islet, D and PP cells. Reduced beta-cell volume density correlated with increased positive staining of 8-OHdG. Japanese Type II diabetic patients show a reduction of beta-cell mass and evidence of increased oxidative stress-related tissue damage that is correlated with the extent of the beta-cell lesions. [Diabetologia (2002) 45: 85–96]

Body Composition, Visceral Fat, Leptin, and Insulin Resistance in Asian Indian Men

Abstract: There is a high prevalence of type 2 diabetes mellitus and coronary artery disease among urban and migrant Asian Indians despite the absence of traditional risk factors. Evidence exists that Asian Indians are more hyperinsulinemic than Caucasians and that hyperinsulinemia may be important in the development of these diseases. To test whether insulin action was related to total or regional adiposity and to explore the potential role of plasma leptin and lipids, we measured insulin-mediated glucose disposal by the euglycemic insulin clamp, adipose distribution and muscle volume using computed axial tomography, and fasting serum leptin and lipid levels in 20 healthy Asian Indian male volunteers (age, 36 ± 10 yr). A mean body mass index of 24.5 ± 2.5 kg/m2 was associated with an unusually high percentage of body fat (33 ± 7%). The majority of the fat was sc, and 16% was visceral (intraabdominal) adipose tissue. The majority (66%) of these nonobese men were insulin resistant. The mean fasting serum leptin leve...