Adrenergic effects on plasma levels of glucagon, insulin, glucose and free fatty acids in rabbits--influences of selective blocking drugs.
Species differences concerning the effects of alpha- and beta-receptor stimulation on glucagon release and carbohydrate metabolism have been reported. The aim of the present study was to investigate how the subtypes of alpha- and beta-receptors regulate the plasma levels of glucagon, insulin, glucose and free fatty acids in fasted rabbits. Epinephrine-induced 1) hyperglucagonaemia, 2) hypoinsulinaemia and 3) hyperglycaemia were significantly inhibited by alpha-2 receptor blockade (yohimbine), and not influenced by alpha-1 receptor blockade (prazosin). Isoproterenol-induced 1) hyperglucagonaemia was not affected by beta-1 or beta-2 receptor blockade, 2) hyperinsulinaemia was inhibited by a lower dose of beta-2 (ICI 118.551) than beta-1 receptor blockade (metoprolol), 3) hyperglycaemia was inhibited by beta-2 receptor blockade and 4) increases in the plasma levels of free fatty acids were blocked by beta-1 receptor blockade. It is concluded that in fasted rabbits: 1) plasma levels of glucagon are mainly increased by alpha-2 receptor stimulation, 2) plasma levels of insulin are decreased by alpha-2 receptor stimulation, and increased more by beta-2 than by beta-1 receptor stimulation, 3) plasma levels of glucose are increased by alpha-2 and beta-2 receptor stimulation and 4) the plasma levels of free fatty acids are increased by beta-1 receptor stimulation.
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000818:Animals; D001786:Blood Glucose / Q000032:analysis*; D004837:Epinephrine / Q000494:pharmacology; D005230:Fatty Acids, Nonesterified / Q000097:blood*; D005260:Female; D005934:Glucagon / Q000097:blood*; D007328:Insulin / Q000097:blood*; D007545:Isoproterenol / Q000494:pharmacology; D008790:Metoprolol / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D011412:Propanolamines / Q000494:pharmacology; D011817:Rabbits; D015016:Yohimbine / Q000494:pharmacology
D000317:Adrenergic alpha-Antagonists; D000319:Adrenergic beta-Antagonists; D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D011412:Propanolamines; D015016:Yohimbine; C026777:ICI 118551; D005934:Glucagon; D008790:Metoprolol; D007545:Isoproterenol; D011224:Prazosin; D004837:Epinephrine