Effect of coinfusion of cholic acid and sulfated cholic acid on bile formation in rats.

The effect of combined infusion of sulfated cholic acid and nonsulfated cholic acid on bile formation was investigated. The data show that the secretion of sulfated cholic acid is slower and does not share the same transport mechanism(s) as nonsulfated cholic acid. Sulfated cholic acid significantly increased bile flow and reduced the secretion of biliary phospholipids, cholesterol, and protein associated with the secretion of exogenous nonsulfated cholic acid, only when they were infused in a ratio higher than 2:1 (sulfated:nonsulfated). Thus it is concluded that sulfated bile acids may protect the liver against the toxic effect of high concentration of bile acids. The relevance of these findings to human cholestasis remains to be determined because sulfated bile acids do not predominate in serum during cholestasis.