Release of amylin from perfused rat pancreas in response to glucose, arginine, beta-hydroxybutyrate, and gliclazide.

ABSTRACT

Amylin is a 37-amino acid peptide isolated from the islet amyloid of patients with non-insulin-dependent diabetes mellitus. The isolated perfused normal rat pancreas was used to evaluate the effects of glucose and insulin secretagogues, such as arginine, beta-hydroxybutyrate, and gliclazide, on amylin secretion. Glucose and the other stimulants tested elicited a significant release of amylin from the rat pancreas in a biphasic pattern, similar to that of insulin. Dose-response studies of the glucose-induced release of amylin and insulin revealed that they possessed a similar dependency on glucose. However, the release of amylin induced by high concentrations of glucose was partially dissociated from that of insulin; that is, the amylin-insulin molar ratios induced by 22.2 and 33.3 mM glucose (1.11 +/- 0.05 and 1.05 +/- 0.04%, respectively) were significantly higher than those induced by 16.7 mM glucose (0.90 +/- 0.04%, P less than 0.01 vs. 22.2 mM glucose, P less than 0.05 vs. 33.3 mM glucose). Additionally, when the basal concentration of glucose in the perfusate was increased from 5.6 to 11.1 mM, the response of amylin was unchanged. These data suggest that amylin may be an islet hormone whose abundant response to high concentrations of glucose might contribute to the oversecretion of amylin in the hyperglycemia that accompanies diabetes mellitus.