Arginine-stimulated acute phase of insulin secretion in non-insulin-dependent diabetes in the young.

The acute insulin response to a 5 g pulse of arginine monohydrochloride was studied in 10 patients with non-insulin-dependent diabetes in the young (NIDDY) and 10 age-, weight- and sex-matched control subjects. All diabetics belonged to families in which non-insulin-dependent diabetes was transmitted through 3 generations. Mean peak insulin responses were similar in both groups (84.1 +/- 10.6; 68.2 +/- 8 microU/ml, p greater than 0.5). However, it is well known that hyperglycaemia accentuates the insulin response to non-glucose stimuli. To test this hypothesis, 5 of the diabetics were subjected to an intravenous insulin tolerance test, prior to the administration of the arginine pulse. At this lowered glucose level, the beta-cell secretory response was significantly decreased in the diabetics (C-peptide peak responses 2.5 +/- 0.3 vs 4.4 +/- 0.7 ng/ml, p less than 0.02). Thus it can be concluded that hyperglycaemia enhances the insulin secretory response to non-glucose stimuli and that following correction of the hyperglycaemia patients with NIDDY have an attenuated insulinaemic response.