Insulin secretion and action in subjects with impaired fasting glucose and impaired glucose tolerance : Results from the veterans administration genetic epidemiology study

• Published in: Diabetes (New York, N.Y.) Vol. 55; no. 5; pp. 1430 - 1435
• Main Authors: ABDUL-GHANI, Muhammad A, JENKINSON, Christopher P, RICHARDSON, Dawn K, TRIPATHY, Devjit, DEFRONZO, Ralph A
• Format: Journal Article
• Language: English
• Published: Alexandria, VA American Diabetes Association 01.05.2006
• Subjects: Adult; Biological and medical sciences; Blood Glucose - genetics; Blood Glucose - metabolism; Body Mass Index; Catheters; Diabetes; Diabetes. Impaired glucose tolerance; Endocrine pancreas. Apud cells (diseases); Endocrinopathies; Epidemiology; Etiopathogenesis. Screening. Investigations. Target tissue resistance; Fasting; Female; Glucose; Glucose Clamp Technique; Glucose intolerance; Glucose Intolerance - blood; Glucose Intolerance - genetics; Glucose Intolerance - physiopathology; Homeostasis; Humans; Insulin resistance; Male; Medical sciences; Metabolism; Mexican Americans - genetics; Middle Aged; Plasma; Risk factors; Texas; Type 2 diabetes; United States; United States Department of Veterans Affairs; Veins & arteries; Veterans; United States; Texas; Endocrinopathy; Human; Pancreatic hormone; Fasting; Secretion; Diabetes mellitus; Genetics; Glucose; Impaired glucose tolerance; Epidemiology; Insulin
• DOI: 10.2337/db05-1200
• ISSN: 0012-1797

This study was conducted to observe changes in insulin secretion and insulin action in subjects with impaired fasting glucose (IFG) and/or impaired glucose tolerance (IGT). A total of 319 subjects were studied with an oral glucose tolerance test (OGTT). Fasting plasma glucose and insulin concentrations were measured at baseline and every 30 min during the OGTT. Fifty-eight subjects also received a euglycemic-hyperinsulinemic clamp. Insulin sensitivity was calculated as the total glucose disposal (TGD) during the last 30 min of the clamp. Homeostasis model assessment of insulin resistance (HOMA-IR) was calculated from fasting plasma glucose and insulin concentrations. Subjects with IFG had TGD similar to normal glucose-tolerant subjects, while subjects with IGT and combined IFG/IGT had significantly reduced TGD. HOMA-IR in subjects with IFG was similar to that in subjects with combined IFG/IGT and significantly higher than HOMA-IR in subjects with IGT or NGT. Insulin secretion, measured by the insulinogenic index (DeltaI(0-30)/DeltaG(0-30)) and by the ratio of the incremental area under the curve (AUC) of insulin to the incremental AUC of glucose (0-120 min), was reduced to the same extent in all three glucose-intolerant groups. When both measurements of beta-cell function were adjusted for severity of insulin resistance, subjects with IGT and combined IFG/IGT had a significantly greater reduction in insulin secretion than subjects with IFG. Subjects with IGT and IFG have different metabolic characteristics. Differences in insulin sensitivity and insulin secretion may predict different rates of progression to type 2 diabetes and varying susceptibility to cardiovascular disease.