Differential effects of amino acids on the isolated perfused rat kidney.
1. The direct effects of individual amino acids, including glycine (a neutral amino acid), L-glutamic acid (an acidic amino acid), L-leucine (a neutral, branched-chain amino acid) and L-arginine (a basic amino acid), on renal function were compared with a mixed amino acid solution by using the isolated rat kidney perfused with a physiological saline solution containing 6.7% (w/v) albumin and a basal level of 2 mmol/l mixed amino acids. 2. In a control series, the renal perfusate flow was stable but the glomerular filtration rate, as measured by [14C]inulin clearance, declined with time. A stable glomerular filtration rate could be obtained by increasing the basal perfusate amino acid concentration to 14 mmol/l. 3. The addition of 6 mmol/l mixed amino acids produced a sustained increase in renal perfusate flow and an increase in [14C]inulin clearance, reversing its time-dependent fall. Sodium reabsorption was enhanced, but, unlike the control series, no increase in fractional albumin excretion was obtained. 4. Renal perfusate flow was increased by glycine (6 mmol/l), L-arginine hydrochloride (6 mmol/l) and sodium glutamate (6 mmol/l) but remained unaffected by L-leucine. The vasodilatation induced by L-arginine hydrochloride and sodium glutamate was not sustained. 5. The time-dependent fall in [14C]inulin clearance was prevented by glycine, L-arginine and glutamic acid, but not by L-leucine. L-Arginine hydrochloride, like the mixed amino acid solution, produced a significant increase in [14C]inulin clearance.(ABSTRACT TRUNCATED AT 250 WORDS)
el Sayed
A A
AA
Department of Medicine, Royal Hallamshire Hospital, Sheffield, U.K.
Haylor
J
J
el Nahas
A M
AM
D000596:Amino Acids / Q000494:pharmacology*; D000818:Animals; D001120:Arginine / Q000494:pharmacology; D005919:Glomerular Filtration Rate / Q000187:drug effects; D005971:Glutamates / Q000494:pharmacology; D005998:Glycine / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D007668:Kidney / Q000098:blood supply / Q000187:drug effects*; D007930:Leucine / Q000494:pharmacology; D008297:Male; D010477:Perfusion; D051381:Rats; D011919:Rats, Inbred Strains; D012039:Regional Blood Flow; D012964:Sodium / Q000378:metabolism
D000596:Amino Acids; D005971:Glutamates; D001120:Arginine; D012964:Sodium; D007930:Leucine; D005998:Glycine