Hormonal mediators of amino acid-induced glomerular hyperfiltration in humans.
It has been speculated that glucoregulatory hormones and/or renal autacoids mediate the increase in glomerular filtration rate (GFR) induced by the administration of protein or amino acids. Because infusion of a mixture of amino acids (AA mix), but not of branched-chain amino acids (BCAA) alone, increases GFR, we performed a crossover study in seven normal subjects in which the glomerular hemodynamic effects of separate 3-h infusions of these two amino acid solutions were compared with changes in potential mediators of this response, i.e., glucoregulatory hormones, renin, vasodilatory prostaglandins (PGs), and guanosine 3',5'-cyclic monophosphate (cGMP). As expected, infusion of the AA mix but not BCAA resulted in a prompt and sustained increase in GFR. Both infusions caused a significant increase in plasma insulin, whereas glucagon increased only with the AA mix. Plasma growth hormone was initially unchanged with both infusions but increased after 2 h of BCAA. Neither infusion significantly increased the urinary excretion of PGE2, 6-keto-PGF1 alpha, or cGMP. Both infusions resulted in a small but significant decrease in plasma renin activity. Infusion of BCAA but not the AA mix resulted in a progressive decrease in plasma glucose and potassium concentrations and an increase in renal sodium reabsorption that may have resulted from stimulation of insulin secretion that was not counterbalanced by a simultaneous increase in glucagon. Thus only changes in glucagon exhibited a significant temporal relationship with changes in GFR, lending further support to a role for glucagon as a mediator of amino acid-induced glomerular hyperfiltration.
Wada
L
L
Medical Service, San Francisco General Hospital Medical Center, California 94110.
Don
B R
BR
Schambelan
M
M
D000328:Adult; D000596:Amino Acids / Q000008:administration & dosage / Q000494:pharmacology*; D000597:Amino Acids, Branched-Chain / Q000008:administration & dosage / Q000494:pharmacology; D001786:Blood Glucose / Q000032:analysis; D006152:Cyclic GMP / Q000502:physiology / Q000652:urine; D015232:Dinoprostone / Q000502:physiology / Q000652:urine; D005919:Glomerular Filtration Rate / Q000187:drug effects*; D005934:Glucagon / Q000097:blood; D013006:Growth Hormone / Q000097:blood; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D007262:Infusions, Intravenous; D007328:Insulin / Q000097:blood; D007668:Kidney / Q000187:drug effects* / Q000502:physiology; D008297:Male; D009569:Nitric Oxide / Q000502:physiology; D011188:Potassium / Q000097:blood; D011453:Prostaglandins / Q000502:physiology / Q000652:urine; D012083:Renin / Q000097:blood / Q000502:physiology
D000596:Amino Acids; D000597:Amino Acids, Branched-Chain; D001786:Blood Glucose; D007328:Insulin; D011453:Prostaglandins; D009569:Nitric Oxide; D013006:Growth Hormone; D005934:Glucagon; D012083:Renin; D006152:Cyclic GMP; D015232:Dinoprostone; D011188:Potassium