Elevated plasma glucose 2-hour post challenge predicts defects in beta-cell function . Byrne, Maria M., Jeppe Sturis, Robert J. Sobel, and Kenneth S. Polonsky. The University of Chicago, Department of Medicine, Pritzker School of Medicine, Chicago, Illinois
APStracts 2:0230E, 1995.
Studies were performed in subjects with no known family history of diabetes, normoglycemic first-degree relatives of subjects with NIDDM, and subjects with non-diagnostic OGTTs (NDX) or impaired glucose tolerance (IGT). Insulin sensitivity index (SI) was similar in all four groups. However a number of defects in insulin secretion were seen in the NDX and IGT groups including: reduced first phase insulin secretory responses to intravenous glucose in relation to the degree of insulin resistance as judged by the percentile rank for AIRg vs SI; reduced normalized spectral power of insulin secretion during oscillatory glucose infusion demonstrating decreased ability of the beta cell to detect and respond to the successive increases and decreases in glucose and therefore to be entrained by the exogenous glucose infusion. The ability of a low dose glucose infusion to prime the insulin secretory response to a subsequent glucose stimulus was normal in subjects with IGT but reduced or absent in subjects with overt NIDDM. These studies demonstrate that a number of alterations in [beta]-cell function are detectable in non -diabetic first degree relatives of subjects with NIDDM with mild elevations in the 2-hr post challenge glucose level and these abnormalities antedate the onset of overt hyperglycemia and clinical diabetes.

Received 8 September 1995; accepted in final form 9 November
1995.
APS Manuscript Number E437-5.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 8 December 95