Selective glutathione depletion on function and structure of the isolated perfused rat kidney

Selective glutathione depletion on function and structure of the isolated perfused rat kidney. The role of glutathione (GSH) in the preservation of renal function and the pathogenesis of renal injury has been investigated using the isolated perfused rat kidney as a model. In kidneys perfused for 80min with 5mM glucose as the only exogenous substrate, tissue GSH becomes depleted, renal function deteriorates, and a degenerative change appears, restricted to the medullary thick ascending limb. These abnormalities can be ameliorated by providing amino acid supplements or by adding GSH itself to the perfusion. To distinguish between the effects of amino acid supplementation and GSH depletion per se, selective depletion of GSH was accomplished in several different ways. Synthesis of GSH was inhibited by the addition of dl-buthionine- SR -sulfoximine, a specific inhibitor of gamma-glutamyl cysteine synthetase. GSH depletion was also produced by 2-cyclohexene-1-one and diethylmaleate, both known to diminish the concentration of GSH selectively without affecting protein thiols. Perfused kidneys selectively depleted of GSH showed significant impairment of concentrating ability, and less marked decreases in tubular reabsorption of sodium. The degenerative changes in the medullary thick ascending limb, on the other hand, were unaltered. While GSH depletion seriously impairs certain renal transport functions, it is probably not responsible for the anatomical disruption of the thick ascending limb that characterizes the isolated perfused rat kidney. Depletion selective en glutathion sur la fonction et la structure du rein de rat perfuse isole. Le role du glutathion (GSH) sur la conservation de la fonction renale et la pathogenie des lesions renales a ete etudie en utilisant un modele de rein de rat perfuse isole. Dans les reins perfuses pendant 80min avec 5mM glucose comme seul substrat exogene, le GSH tissulaire diminue, la fonction renale s'altere, et des modifications degeneratives apparaissent, limitees a l'anse ascendante large medullaire. Ces anomalies peuvent etre ameliorees en apportant des supplements en amino-acides, ou en ajoutant le GSH lui meme a la perfusion. Afin de distinguer entre les effets de la supplementation en acides amines et ceux de la depletion en GSH elle meme, une depletion selective en GSH a ete effectuee de plusieurs manieres differentes. La synthese du GSH etait inhibee par l'addition de dl-buthione- SR -sulfoximine, un inhibiteur specifique de la gamma-glutamyl cysteine synthetase. La depletion en GSH etait egalement produite par le 2-cyclohexene-1-one et le diethylmaleate, connus tous les deux pour diminuer selectivement la concentration de GSH sans affecter les thiols proteiniques. Des reins perfuses selectivement depletes en GSH avaient une diminution significative de la capacite de concentration, et des diminutions moins marquees de la reabsorption tubulaire du sodium. Les modifications degeneratives de l'anse ascendante large medullaire, par ailleurs, etaient inchangees. Alors que la depletion en GSH altere serieusement certaines fonctions de transport renal, elle n'est probablement pas responsable de l'interruption anatomique de l'anse ascendante large qui caracterise le rein de rat perfuse isole.