title: Glucagon secretion from the perfused rat pancreas. Studies with glucose and catecholamines.
abstract: The isolated in situ perfused rat pancreas was used to study glucose and catecholamine control of glucagon secretion, and to investigate the possible role of endogenous cyclic AMP as a mediator of this secretory process. When perfusate glucose was acutely dropped from 100 to 25 mg/100 ml, glucagon was released in a biphasic pattern with an early spike and a later plateau-like response. 300 mg/100 ml glucose suppressed glucagon secretion to near the detection limit of the radioimmunoassay (15 pg/ml). When perfusate glucose was dropped from 300 to 25 mg/100 ml, a delayed, relatively small peak occurred suggesting persisting alpha cell suppression by prior high glucose exposure. 2-Deoxy d-glucose stimulated glucagon secretion and inhibited insulin secretion. Glucagon was secreted in a biphasic pattern in response to both 2.7 x 10(-7) M epinephrine and norepinephrine. The glucagon response to epinephrine was markedly suppressed by glucose at 300 mg/100 ml, and the biphasic response pattern was obliterated. Glucose evoked a two-phase insulin secretory pattern, and the second phase was markedly and rapidly inhibited by epinephrine. Pancreases were perfused with glucose at 300 mg/100 ml which was then lowered to 80 mg/100 ml. 5 min later, epinephrine was infused and definite blunting of the first-phase spike occurred. 10 mM theophylline produced modest rapid uniphasic stimulation of glucagon release, and, in addition, caused enhancement of epinephrine-stimulated glucagon release. An inhibitory influence upon epinephrine-stimulated glucagon was observed as well. Insulin secretion was stimulated by 10 mM theophylline, and this stimulation was inhibited by epinephrine.
mesh_terms: D000818:Animals; D000242:Cyclic AMP / Q000502:physiology; D003847:Deoxyglucose / Q000502:physiology; D003864:Depression, Chemical; D004357:Drug Synergism; D004837:Epinephrine / Q000494:pharmacology*; D005934:Glucagon / Q000378:metabolism*; D005947:Glucose / Q000032:analysis / Q000494:pharmacology* / Q000502:physiology; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology*; D010179:Pancreas / Q000187:drug effects* / Q000378:metabolism; D010477:Perfusion; D011863:Radioimmunoassay; D051381:Rats; D013806:Theophylline / Q000494:pharmacology
chemical_list: D007328:Insulin; D005934:Glucagon; D003847:Deoxyglucose; D013806:Theophylline; D000242:Cyclic AMP; D005947:Glucose; D009638:Norepinephrine; D004837:Epinephrine