RELATIONSHIPS BETWEEN BETA-CELL FUNCTION AND DIABETIC DURATION AND ALBUMINURIA IN TYPE-2 DIABETES-MELLITUS

To clarify whether beta-cell function deteriorates with increasing alb uminuria and duration of diabetes, we investigated the insulin and c-p eptide response to oral glucose tolerance test in 47 healthy subjects and 75 normoalbuminuric (group 1), 30 microalbuminuric (group 2), and 35 macroalbuminuric (group 3) Type 2 diabetes mellitus patients. The t otal area under the insulin curve (AUCI) values of groups 1, 2, and 3 were 245 +/- 16, 193 +/- 17, and 88 +/- 8 pmol/L . h, respectively, si gnificantly lower than that (624 +/- 34 pmol/L . h) of the healthy gro up. The mean total area under the c-peptide cur?ie (AUCC-P) values of groups 1, 2, and 3, respectively, were 2.50 +/- 0.11, 2.05 +/- 0.15, a nd 1.73 +/- 0.07 nmol/L . h, respectively, significantly lower than th at (5.47 +/- 0.19 nmol/L . h) of healthy controls. The mean AUCI and A UCC-P values of group 3 were significantly reduced compared to those o f group 1. The mean AUCI and AUCC-P values of patients with 0-5, 5-10, 10-15, and >15 years' duration were significantly decreased compared to those of healthy subjects. The mean AUCI and AUCC-P values of patie nts with >15 years' duration were significantly lower than those of pa tients with 0-5 years' duration. The mean hemoglobin Ale values of the three diabetic groups were not significantly different. These data su ggest that beta-cell function deterioration was associated with increa sing albuminuria and diabetic duration in Type 2 diabetic patients.