title: Forskolin-induced activation of adenylate cyclase, cyclic adenosine monophosphate production and insulin release in rat pancreatic islets.
abstract: Forskolin activated adenylate cyclase in rat islet homogenates and stimulated cAMP production in intact islets incubated in the absence or presence of either D-glucose or Ca2+. Forskolin failed to affect D-[U-14C]glucose oxidation, glucose-stimulated net 45Ca uptake, or basal insulin release, but enhanced insulin secretion evoked by either nutrients (D-glucose, 2-ketoisocaproate, L-leucine alone or in combination with L-glutamine), or nonnutrient secretagogues (12-O-tetradecanoylphorbol-13-acetate, Ba2+ alone or in combination with theophylline). Forskolin stimulated insulin release from islets incubated in the presence of glucose but in the absence of Ca2+. These findings confirm that a marked increase in cAMP production is not sufficient to cause sustained insulin release. They also suggest that the enhancing action of endogenous cAMP upon insulin release does not depend on a facilitation of Ca2+ influx into islet cells.
mesh_terms: D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000262:Adenylyl Cyclases / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology; D005576:Colforsin; D000242:Cyclic AMP / Q000096:biosynthesis*; D004224:Diterpenes / Q000494:pharmacology*; D005947:Glucose / Q000378:metabolism; D006019:Glycolysis / Q000187:drug effects; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D051381:Rats
chemical_list: D004224:Diterpenes; D007328:Insulin; D005576:Colforsin; D000242:Cyclic AMP; D000262:Adenylyl Cyclases; D005947:Glucose; D002118:Calcium; D015056:1-Methyl-3-isobutylxanthine