Involvement of renal autacoids in the direct effects of mixed amino acids on the kidney.

A pharmacological approach has been employed to investigate the involvement of renal autacoids in the direct effect of amino acids on the isolated rat kidney. The increase in renal perfusate flow induced by 6 mM mixed amino acids was inhibited by sulpiride, a dopamine antagonist. The change in GFR induced by 6 mM mixed amino acids was abolished by L-nitro-arginine methyl ester, an inhibitor of nitric oxide biosynthesis and partially inhibited by either sulpiride or indomethacin. It is concluded that several autacoids may mediate the direct effect of amino acids on the kidney with dopamine being primarily involved in hyperperfusion and nitric oxide involved primarily in hyperfiltration.