Epinephrine-induced hypoaminoacidemia in normal and diabetic human subjects: effect of beta blockade.
To evaluate the effect of epinephrine on the circulating amino acids, we infused epinephrine into normal human subjects and juvenile-onset diabetic patients given a constant basal infusion of insulin. Epinephrine infusion produced an identical 350--400 pg/ml rise in plasma epinephrine in both groups. In normal subjects, epinephrine caused a progressive 26% reduction in total circulating amino acids, despite unchanged levels of plasma insulin. This effect was most pronounced for the branched amino acids, which fell by 40% (P < 0.001). Plasma alanine was the only amino acid which failed to decline. Similarly, infusion of epinephrine in the insulin-infused diabetics produced a 23% fall in total amino acids, a 37% decline in branched chain amino acids, but no change in plasma alanine. Saline infusion in the insulin-infused diabetics had no effect on plasma amino acid concentrations. In addition, when epinephrine was infused into two insulin-withdrawn diabetics, a comparable hypoaminoacidemic response was observed. The infusion of propranolol in both normal and diabetic subjects totally prevented the epinephrine-induced fall in plasma amino acids. It is concluded that (1) increments in epinephrine similar to those observed in stress cause a decline in circulating amino acids (except alanine) which is greatest for the branched chain amino acids; (2) this hypoaminoacidemic effect occurs in the absence of a rise in plasma insulin and diabetic subjects, as well; and (3) epinephrine-induced changes in amino acid regulation are prevented by beta-adrenergic blockade. Our findings suggest that, in contrast with glucose and fat metabolism, epinephrine and insulin may have similar, rather than antagonistic, effects on plasma amino acid metabolism.
D000328:Adult; D000596:Amino Acids / Q000097:blood*; D001786:Blood Glucose / Q000378:metabolism; D003922:Diabetes Mellitus, Type 1 / Q000378:metabolism*; D004837:Epinephrine / Q000097:blood; D005260:Female; D005934:Glucagon / Q000097:blood; D006801:Humans; D007328:Insulin / Q000097:blood; D007700:Kinetics; D008297:Male; D011433:Propranolol; D012016:Reference Values
D000596:Amino Acids; D001786:Blood Glucose; D007328:Insulin; D005934:Glucagon; D011433:Propranolol; D004837:Epinephrine