Characterization of the insulinotropic action of a phospholipase A(2) isolated from Crotalus durissus collilineatus rattlesnake venom on rat pancreatic islets

Abstract

The ability of PLA(2) and crotapotin, isolated from Crotalus durissus collilinearus rattlesnake venom. to stimulate insulin secretion from isolated rat islets was examined. PLA(2) and crotapotin stimulated insulin secretion at 2.8 mmol/L glucose. whereas at a high glucose concentrations (16.7 mmol/L) only PLA(2) stimulated secretion. Nifedipine (10 mumol/L) did not alter the ability of PLA(2) to increase insulin secretion stimulated by a depolarizing concentration of K+ (30 mmol/L). PLAN did not affect (CO2)-C-14 production but significantly increased the efflux of arachidonic acid from isolated islets. These results indicate that PLA(2)-stimulated secretion is not dependent on an additional influx of Ca2+ through L-type Ca2+-channels but rather is associated with arachidonic acid formation in pancreatic islets. (C) 2004 Elsevier Ltd. All rights reserved.