[Hyperglycemia and inhibition of glucose-induced insulin release in 6-aminonicotinamide treated rats]

The effects of 6-aminonicotinamide (6-AN) on blood glucose and insulin release were studied in rats. 6-AN at 4mg/100g body weight slowly raised blood glucose concentrations to a significantly higher level than the control values 6 hours after an intraperitoneal injection. At this time severe glucose intolerance and low IRI response were noticed during an intravenous glucose tolerance test. Adrenalectomized rats replaced by hydrocortisone also presented hyperglycemia, glucose intolerance and low IRI response during IVGTT under treatment with 6-AN but to a lesser extent than in the intact rats. In in vitro experiments, decreased insulin release from the perfused pancreata of rats pretreated with 6-AN was found both in the 1st and 2nd phases of response to glucose stimulation. These data indicate that 6-AN-induced hyperglycemia is attributed to the inhibition of insulin release in adrenalectomized rats except for the hypothetical effect of 6-AN which diminishes an action of insulin on cellular glucose transport.