Role of glucagon in disposal of an amino acid load.
Amino acids stimulate the release of glucagon and insulin. To assess the role of aminogenic hyperglucagonemia, we have studied, in healthy young males, the effects of basal (less than 100 pg/ml) and high (200-400 pg/ml) plasma glucagon concentrations on amino acid metabolism during intravenous infusion (0.5 g.h-1.4 h) of a mixture of 15 amino acids. Basal plasma glucagon concentrations were obtained by infusion of somatostatin (0.5 mg/h) plus glucagon (0.25 ng.kg-1.min-1) and high plasma glucagon concentrations by infusion of somatostatin plus glucagon (3.0 ng.kg-1.min-1) or by infusion of amino acids alone. All studies were performed under conditions of euglycemic (83-91 mg/dl) hyperinsulinemia (50-80 microU/ml). Hyperglucagonemia significantly increased 1) net amino acid transport from the extracellular into the intracellular space (by approximately 4%), 2) net degradation of amino acids entering the intracellular space (by approximately 40%), and 3) conversion of degraded amino acids into glucose from 0-10% (basal glucagon) to 70-100% (high glucagon). Hyperglucagonemia did not affect the amount of amino acids excreted in the urine (approximately 4%). We conclude that glucagon plays an important role in the disposition of amino acids by increasing their inward transport, their degradation, and their conversion into glucose.
Boden
G
G
Department of Medicine, Temple University School of Medicine, Philadelphia 19140.
Tappy
L
L
Jadali
F
F
Hoeldtke
R D
RD
Rezvani
I
I
Owen
O E
OE
D000328:Adult; D000596:Amino Acids / Q000097:blood / Q000378:metabolism*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005934:Glucagon / Q000097:blood / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D015309:Glucose Clamp Technique; D013006:Growth Hormone / Q000097:blood; D006801:Humans; D007328:Insulin / Q000097:blood / Q000494:pharmacology*; D007700:Kinetics; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D011994:Recombinant Proteins / Q000494:pharmacology; D013004:Somatostatin / Q000494:pharmacology
D000596:Amino Acids; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D011994:Recombinant Proteins; D013004:Somatostatin; D013006:Growth Hormone; D005934:Glucagon; D005947:Glucose