Investigations on isolated islets of langerhans in vitro. 16.Modification of the glucose-dependent inhibition of glucagon secretion.
Investigation of glucagon secretion in isolated Wistar rat islets was carried out to elucidate further the regulatory function of glucose and arginine on pancreatic A-cells. The suppressive effect of D-glucose could also be demonstrated with L-glucose, D-mannose, D-fructose, D-galactose, D-glyceraldehyde and DL-dihydroxyacetone, but not in the presence of 3-O-methylglucose or mannitol. Sugars other than D-glucose inhibited glucagon secretion only at much higher concentrations than those at which D-glucose was effective. Furthermore, although 7.5 mM D-glucose up to 80% inhibition, the effects of other sugars appeared to level off at only 50--60% inhibition. The inhibitory action of D-glucose or D-glyceraldedyde on glucagon secretion could not be overcome by L-arginine, but 3-O-methylglucose, mannoheptulose, 2-deoxy-D-glucose, iodoacetamide, theophylline, epinephrine and acetylcholine were effective. The insulin secretion in response to glucose was inhibited by the metabolic inhibitors used, whereas the B-cell response in the presence of glyceraldehyde was diminished by iodoacetamide only. Like D-glucose, a variety of other sugars markedly reduced the stimulatory effect of L-arginine in glucagon release. The results show that the suppression of glucagon secretion is not specific for D-glucose and not strongly connected on a stimulated insulin secretion.
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001120:Arginine / Q000494:pharmacology*; D002241:Carbohydrates / Q000494:pharmacology; D004837:Epinephrine / Q000494:pharmacology; D005260:Female; D005934:Glucagon / Q000378:metabolism*; D005947:Glucose / Q000494:pharmacology*; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D007460:Iodoacetamide / Q000494:pharmacology; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D051381:Rats; D013806:Theophylline / Q000494:pharmacology
D002241:Carbohydrates; D007328:Insulin; D005934:Glucagon; D001120:Arginine; D013806:Theophylline; D005947:Glucose; D000109:Acetylcholine; D004837:Epinephrine; D007460:Iodoacetamide