| Abstract: | The conjugate pattern of biliary 14C]bile acids was investigated in isolated perfused rat livers, which were infused with either 24-14C]cholic acid or 24-14C]chenodeoxycholic acid (40 mumol/h) together with or without taurine or cysteine (80 mumol/h). 14C]Bile acids were chromatographed on a thin-layer plate and the distribution of radioactivity on the plate was measured by radioscanning. The biliary excretion of 14C]bile acids was greater in the infusion with 14C]cholic acid than in the infusion with 14C]chenodeoxycholic acid. Biliary unconjugated 14C]bile acids amounted to about 50% of the total after the infusion with 14C]cholic acid, while only about 10% with 14C]chenodeoxycholic acid. In the initial period of infusion, biliary conjugated 14C]bile acids consisted mostly of the taurine conjugate, which decreased with time and the glycine conjugate increased complementarily. When taurine was simultaneously infused, the decrease in the taurine conjugate was suppressed to some extent. Cysteine infused in place of taurine had a similar influence but was less effective than taurine. The taurine content of liver after the infusion with either of the 14C]bile acids decreased greatly compared with that before the infusion, even when taurine or cysteine was infused simultaneously. The glycine content also decreased after the infusion, but the decrease in glycine was smaller than that in taurine. The results suggest that the conjugate pattern of biliary bile acids in rats depends mainly on the amount of taurine which is supplied to hepatic cells either exogenously from plasma or endogenously within themselves. |
