Nonparticipation of extracellular glutathione in renal transport of dibasic amino acids.
Microinjections of L-[14C]arginine (2.9 mM) and L-[14C]ornithine (3.4 mM) were made into renal proximal tubules of rats in the presence of methionine sulfoximine (MSO) (10, 20 mM), ATP (10 mM), and MgCl2 (20 mM) together. Absorption of both labelled amino acids dropped, respectively, by 31.1 and 49.1% compared with control microinjections. The MSO alone or ATP plus MgCl2 had no effect. These data suggest that the inhibition by MSO plus ATP plus MgCl2 is not due to direct competition between MSO and dibasic amino acids but rather to suppression of the renewal of intracellular glutathione. Such an effect is discussed in comparison with cycloleucine inhibition of dibasic amino acid transport. Addition of exogenous glutathione to microinjectates die not reverse either type of inhibition. This study shows that while intracellular glutathione may affect amino acid transport, extracellular glutathione has no effect.
D000042:Absorption; D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D001120:Arginine / Q000378:metabolism; D003515:Cycloleucine / Q000494:pharmacology; D005260:Female; D005978:Glutathione / Q000502:physiology*; D007668:Kidney / Q000187:drug effects / Q000378:metabolism*; D007687:Kidney Tubules, Proximal / Q000378:metabolism; D008717:Methionine Sulfoximine / Q000494:pharmacology; D009952:Ornithine / Q000378:metabolism; D051381:Rats
D000596:Amino Acids; D003515:Cycloleucine; D008717:Methionine Sulfoximine; D001120:Arginine; D009952:Ornithine; D005978:Glutathione