METABOLISM OF CYCLIC-AMP AND GLUCOSE IN ISOLATED ISLETS FROM ACOMYS-CAHIRINUS

Glucose-induced cyclic[c](3H)AMP accumulation, insulin secretory responses and the metabolism of glucose were studied in pancreatic islets from Acomys cahirinus. Glucose [27.7 mmol/l] stimulated neither islet (3H)cAMP accumulation nor insulin release during the 1st 5 min of incubation. Stimulation by glucose of (3H)cAMP was observed after 15 min of incubation and insulin release was markedly stimulated between 15 and 30 min. The utilization of glucose, measured as the production of (3H)2O from (5-3H) glucose was stimulated by glucose after 10 min and proceeded at an apparently linear rate during a 20 min incubation period. In incubations of 5 min, glibenclamide, glucagon or chloromercuribenzene-p-sulfonic acid failed to stimulate islet (3H)cAMP accumulation. 3-Isobutyl-1-methylxanthine in a concentration of 1.0 mmol/l was the only agent tested that elevated rapidly (1 min) islet (3H)cAMP. None of the agents tested elicited an insulin secretory response in 5 min incubations. No gross defect is apparent in the utilization of glucose by Acomys islets; the secretory derangement of the Acomys is associated with a delayed cAMP response to glucose, however, a decreased level of cAMP cannot be the sole explanation for the delayed insulin secretion in the Acomys.