title: Effect of glucose on plasma glucagon and free fatty acids during prolonged exercise.
abstract: The effects of glucose ingestion on the changes in blood glucose, FFA, insulin and glucagon levels induced by a prolonged exercise at about 50% of maximal oxygen uptake were investigated. Healthy volunteers were submitted to the following procedures: 1. a control test at rest consisting of the ingestion of 100 g glucose, 2. an exercise test without, or 3. with ingestion of 100 g of glucose. Exercise without glucose induced a progressive decrease in blood glucose and plasma insulin; plasma glucagon rose significantly from the 60th min onward (+45 pg/ml), the maximal increase being recorded during the 4th h of exercise (+135 pg/ml); plasma FFA rose significantly from the 60th min onward and reached their maximal values during the 4th h of exercise (2177 +/- 144 muEq/l, m +/- SE). Exercise with glucose ingestion blunted almost completely the normal insulin response to glucose. Under these conditions, exercise did not increase plasma glucagon before the 210th min; similarly, the exercise-induced increase in plasma FFA was markedly delayed and reduced by about 60%. It is suggested that glucose availability reduces exercise-induced glucagon secretion and, possibly consequently, FFA mobilization.
mesh_terms: D000284:Administration, Oral; D000328:Adult; D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified / Q000097:blood*; D005934:Glucagon / Q000097:blood*; D005947:Glucose / Q000008:administration & dosage / Q000494:pharmacology*; D006801:Humans; D007328:Insulin / Q000097:blood; D008297:Male; D005082:Physical Exertion
chemical_list: D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D005934:Glucagon; D005947:Glucose