title: Inhibitory effects of rimorphin and dynorphin on insulin secretion from the isolated, perfused rat pancreas.
abstract: In order to settle the question about whether or not opioid peptides stimulate or inhibit insulin secretion, we studied effects of rimorphin and dynorphin, two members of the preproenkephalin B group, on glucose-induced insulin secretion in the isolated, perfused rat pancreas. These peptides (3.95 X 10(-8) M), like morphine (3.95 X 10(-8) M), significantly inhibited the glucose-induced insulin secretion. The inhibitory effect of rimorphin was attenuated by naloxone (1.2 X 10(-6) M) and phentolamine (10(-6) M), suggesting an involvement of adrenergic alpha receptors in the inhibition of glucose-induced insulin secretion mediated through specific opiate receptors. Rimorphin also inhibited glucose-induced insulin secretion even in the cysteamine-treated rat pancreas from which somatostatin had been depleted. Thus, somatostatin does not appear to play a major regulatory role in the insulin secretion in the pancreas.
mesh_terms: D000818:Animals; D004399:Dynorphins / Q000031:analogs & derivatives* / Q000494:pharmacology*; D004723:Endorphins / Q000494:pharmacology*; D005947:Glucose / Q000494:pharmacology; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D008297:Male; D009020:Morphine / Q000494:pharmacology; D010179:Pancreas / Q000187:drug effects / Q000378:metabolism*; D010646:Phentolamine / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013004:Somatostatin / Q000502:physiology
chemical_list: D004723:Endorphins; D007328:Insulin; D013004:Somatostatin; D004399:Dynorphins; D009020:Morphine; C036200:rimorphin; D011433:Propranolol; D005947:Glucose; D010646:Phentolamine