Taurine metabolism in the rat: effect of partial hepatectomy

1. The biosynthesis of taurine in rat liver regenerating after partial hepatectomy is altered such that hypotaurine accumulates and the concentration of taurine is reduced. 2. [35S]Cystine is converted to both [35S]hypotaurine and [35S]taurine in the liver regenerating after partial hepatectomy, whereas only [35S]taurine could be detected in the liver of sham-operated rats. 3. The changes in activities of enzymes involved in this pathway, cystathionase (which increases), cysteinesulfinic acid decarboxylase (which decreases) and hypotaurine aminotransferase (which is unchanged), do not provide an adequate explanation of these observations. 4. We conclude that the oxidation step in which hypotaurine is converted to taurine is altered in this condition, although a convincing demonstration of this enzymatic reaction in vitro has not been accomplished to date.