METABOLISM OF CYSTEINE IS MODIFIED DURING THE ACUTE-PHASE OF SEPSIS IN RATS

In vivo cysteine metabolism during the inflammatory state has been stu died minimally, We investigated cysteine metabolism (i.e. taurine, sul fate and glutathione formation) using a single dose of [S-35] cysteine in septic rats that had been injected with live Escherichia coli into the tail vein and in control, pair-fed rats. Cysteine metabolites wer e separated by ion exchange chromatography, and radioactivity was coun ted in the different fractions. Radioactivity incorporated in tissue p roteins was also measured after protein precipitation. [S-35]Sulfate p roduction was significantly lower in septic rats than in pair-fed rats , S-35] taurine contents were significantly lower only in kidneys, spl een and gastrointestinal tract of septic rats, The higher production o f [S-35] taurine in the livers (the major site of taurine production) of septic rats could have a protective effect against oxidation. Gluta thione concentrations were also significantly greater in liver,spleen, kidneys and gastrocnemius muscle of septic rats, presumably in order to combat oxidative stress induced by sepsis. [S-35]Cysteine incorpora tion in glutathione was significantly higher in spleen and kidneys but not in liver of septic rats compared to pair-fed rats. This could be explained by the fact that, in liver, a greater amount of labeled glut athione had been utilized for host defense, or by a high level in glut athione turnover. Finally, [S-35]cysteine incorporation into protein, in septic rats, was significantly greater than in pair-fed rats in spl een, lung and particulary in whole plasma proteins other than albumin, which mainly represent the acute-phase proteins, These data suggest a n increased requirement for cysteine during sepsis in rats.