Mastoparan, a wasp venom, stimulates insulin release by pancreatic islets through pertussis toxin sensitive GTP-binding protein.
A wasp venom, mastoparan, rapidly stimulated insulin release by rat pancreatic islets in a dose-related manner. The amount of insulin released in response to 58 microM mastoparan far exceeded that induced by 27.8 mM glucose. Mastoparan stimulated insulin release to similar degrees at ambient glucose concentrations of 1.7 mM and 5.6 mM. The islets obtained from pertussis toxin-treated rats showed unequivocally less response to mastoparan. Pretreatment of islets with bromophenacyl bromide, a phospholipase A2 inhibitor, abolished their responsiveness to mastoparan. Pretreatment of islets with nifedipine, a Ca2+ channel blocker, was without effect. Mastoparan is a unique stimulator of insulin release by the pancreatic islets, which acts through GTP-binding protein(s) and phospholipase A2.
Yokokawa
N
N
Department of Gerontology, Endocrinology and Metabolism, School of Medicine, Shinshu University, Nagano-ken, Japan.
Komatsu
M
M
Takeda
T
T
Aizawa
T
T
Yamada
T
T
D000098:Acetophenones / Q000494:pharmacology; D000818:Animals; D001514:Bee Venoms / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D019204:GTP-Binding Proteins / Q000502:physiology*; D005947:Glucose / Q000494:pharmacology; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D036341:Intercellular Signaling Peptides and Proteins; D007515:Islets of Langerhans / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D009543:Nifedipine / Q000494:pharmacology; D010455:Peptides; D037342:Pertussis Toxin; D010741:Phospholipases A / Q000037:antagonists & inhibitors / Q000502:physiology; D054467:Phospholipases A2; D051381:Rats; D011919:Rats, Inbred Strains; D010566:Virulence Factors, Bordetella / Q000494:pharmacology*; D014862:Wasp Venoms / Q000494:pharmacology*
D000098:Acetophenones; D001514:Bee Venoms; D007328:Insulin; D036341:Intercellular Signaling Peptides and Proteins; D010455:Peptides; D010566:Virulence Factors, Bordetella; D014862:Wasp Venoms; C037500:mastoparan; D037342:Pertussis Toxin; D010741:Phospholipases A; D054467:Phospholipases A2; D019204:GTP-Binding Proteins; D009543:Nifedipine; D005947:Glucose; C006821:4-bromophenacyl bromide