Increased insulin clearance in peroxisome proliferator-activated receptor gamma2 Pro12Ala.

The Pro12Ala polymorphism of the peroxisome proliferator-activated receptor (PPARgamma(2)) is associated with reduced risk for type 2 diabetes. Although increased insulin sensitivity of glucose disposal and lipolysis has been reported, the exact mechanism by which the risk reduction is conferred is not clear. Because the conclusion of greater insulin sensitivity hinged upon lower insulin levels in some studies, it is possible that more efficient insulin clearance is involved.

Relationship of serum adiponectin and leptin concentrations with body fat distribution in humans.

Objective: We investigated whether serum concentrations of adiponectin are determined by body fat distribution and compared the findings with leptin.

Research Methods And Procedures: Serum concentrations of adiponectin and leptin were measured by radioimmunoassay (n = 394) and analyzed for correlation with sex, age, and body fat distribution, i.e.

Plasma adiponectin concentrations predict insulin sensitivity of both glucose and lipid metabolism.

In animals, the adipocyte-derived hormone adiponectin has been shown to improve insulin sensitivity, a key factor in the pathogenesis of type 2 diabetes. In Pima Indians, high plasma adiponectin levels are associated with increased insulin sensitivity and reduced risk of type 2 diabetes. It is unclear whether this is also the case in white individuals and whether an additional beneficial effect on lipid metabolism exists.

Acute effect of glimepiride on insulin-stimulated glucose metabolism in glucose-tolerant insulin-resistant offspring of patients with type 2 diabetes.

Objective: This study addressed whether acute infusion of glimepiride influences glucose metabolism independent of its effect on insulin secretion.

Research Design And Methods: Ten healthy, glucose-tolerant but insulin-resistant probands were subjected to a placebo-controlled, double-blind, cross-over study. Each individual received infusions of either 0.

The prevalent Glu23Lys polymorphism in the potassium inward rectifier 6.2 (KIR6.2) gene is associated with impaired glucagon suppression in response to hyperglycemia.

Genetic factors play an important role in the pathogenesis of type 2 diabetes. The relevance to type 2 diabetes of the common polymorphism Glu23Lys in the potassium inward rectifier 6.2 (KIR6.

Relationships among age, proinsulin conversion, and beta-cell function in nondiabetic humans.

The aim of the present study was to examine the relationships among beta-cell function, proinsulin conversion to insulin, and age. We studied insulin and proinsulin secretion in nondiabetic subjects during an oral glucose tolerance test (OGTT) using published indexes of beta-cell function (n = 379, age 16--68 years) and a modified hyperglycemic clamp (10 mmol/l, additional glucagon-like peptide [GLP-1] infusion, final arginine bolus; n = 50, age 19--68 years). Proinsulin conversion to insulin was assessed using proinsulin/insulin (PI/I) ratios immediately after an acute stimulus (OGTT, 30 min; hyperglycemic clamp, 2.