The impact of treatment on insulin release and relative peripheral resistance during the oral glucose tolerance test. A study of noninsulin-dependent diabetes mellitus and glucose intolerance.

Using 75 g oral glucose tolerance tests (OGTTs), insulin release and relative peripheral resistance were studied in two groups of subjects before and after treatment; ten mostly obese subjects with glucose intolerance (GI), who had improved glucose tolerance after six months of diet and exercise with weight reduction; nine nonobese patients with noninsulin-dependent diabetes mellitus (NIDDM), who received a daily dose of 5 mg glipizide for three months. Total insulin release was measured as the total area under the insulin curve during the OGTT. The insulin response to glucose was expressed as the ratio of the incremental area under the insulin curve to that of the glucose curve above fasting levels (delta AUCI/delta AUCG), during the first 30 minutes and the latter part of the test. The glucose uptake rate (M) was measured as the difference between the glucose load and the increase of glucose in the glucose space after compared to before the OGTT. The relative peripheral resistance (rel-R) against glucose-uptake-promoting factors was expressed as 1/M. The main effects of therapy in the GI-group appeared to be a decrease of the mean rel-R value and a decrease of the mean total insulin release. This implies a mainly peripheral action of therapy at receptor and/or postreceptor levels. The mean [delta AUCI/delta AUCG]0-30 value was unchanged and the mean [delta AUCI/delta AUCG]30-120 value was only slightly increased at follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)