An involvement of alpha-adrenergic stimulation in exercise-induced hypoglycemia.
Hypoglycemia developed in fasted rats during forced swimming. This hypoglycemia was mostly abolished by phentolamine, an alpha-adrenolytic agent, or by hexamethonium; was potentiated by propranolol, a beta-adrenolytic agent, of by 5-methoxyindole-2-carboxylic acid, a gluconeogenic inhibitor; and was not affected by anti-insulin serum. The turnover rate of blood glucose estimated from the decay curve of blood [14C]glucose increased significantly during exercise. There was a slight but significantly increase during exercise in the transfer of 3-O-methyl-[14C]glucose into muscle and adipose tissues, when it was corrected for by [3H]mannitol transfer to the same tissues. It is concluded that the alpha-receptor-mediated action of endogenous catecholamine stimulates peripheral glucose utilization leading to hypoglycemia during exercise. The action of alpha- and beta-adrenergic mechanisms, directly on peripheral tissues or via insulin secretion, in fine regulation of blood glucose level is discussed.
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D002395:Catecholamines / Q000378:metabolism; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005943:Gluconeogenesis / Q000187:drug effects; D005947:Glucose / Q000378:metabolism; D006003:Glycogen / Q000378:metabolism; D006584:Hexamethonium Compounds / Q000494:pharmacology; D007003:Hypoglycemia / Q000503:physiopathology*; D007328:Insulin / Q000172:deficiency; D008297:Male; D010646:Phentolamine / Q000494:pharmacology; D005082:Physical Exertion; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D011941:Receptors, Adrenergic / Q000187:drug effects; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects; D013550:Swimming; D013997:Time Factors
D001786:Blood Glucose; D002395:Catecholamines; D005230:Fatty Acids, Nonesterified; D006584:Hexamethonium Compounds; D007328:Insulin; D011941:Receptors, Adrenergic; D011942:Receptors, Adrenergic, alpha; D006003:Glycogen; D011433:Propranolol; D005947:Glucose; D010646:Phentolamine