Characterization of the insulinotropic action of a phospholipase A2 isolated from Crotalus durissus collilineatus rattlesnake venom on rat pancreatic islets.
The ability of PLA2 and crotapotin, isolated from Crotalus durissus collilineatus rattlesnake venom, to stimulate insulin secretion from isolated rat islets was examined. PLA2 and crotapotin stimulated insulin secretion at 2.8 mmol/L glucose, whereas at a high glucose concentrations (16.7 mmol/L) only PLA2 stimulated secretion. Nifedipine (10 micromol/L) did not alter the ability of PLA2 to increase insulin secretion stimulated by a depolarizing concentration of K+ (30 mmol/L). PLA2 did not affect 14CO2 production but significantly increased the efflux of arachidonic acid from isolated islets. These results indicate that PLA2-stimulated secretion is not dependent on an additional influx of Ca2+ through L-type Ca(2+)-channels but rather is associated with arachidonic acid formation in pancreatic islets.
Nogueira
Tatiane C A
TC
Departamento de Fisiologia e Biofísica and Departamento de Bioquímica, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), CP 6109, Campinas, SP 13083-970, Brazil.
Ferreira
Fabiano
F
Toyama
Marcos H
MH
Stoppiglia
Luiz Fabrizio
LF
Marangoni
Sergio
S
Boschero
Antonio C
AC
Carneiro
Everardo M
EM
D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism; D003435:Crotalid Venoms / Q000737:chemistry* / Q000494:pharmacology; D003439:Crotoxin / Q000494:pharmacology; D066298:In Vitro Techniques; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D010741:Phospholipases A / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D054467:Phospholipases A2; D051381:Rats; D017208:Rats, Wistar
D003435:Crotalid Venoms; D007328:Insulin; D016718:Arachidonic Acid; D003439:Crotoxin; D010741:Phospholipases A; D054467:Phospholipases A2