No abstract

This study investigated the influence of dehydrocholic acid (DHCA) infusion on the secretion of endogenous bile acids, and biliary lipids in rats in an attempt to explain the reduction of biliary lipid secretion associated with DHCA infusion. DHCA increased bile flow and the bile acids produced during the infusion were composed of three hydroxy-oxo metabolites (83–93%), and cholic acid (6–14%). Very little DHCA was secreted unchanged ( < 2%). The secretions of all the endogenous biliary bile acids were diminished within 30–60 min of infusion. DHCA furthermore reduced the secretion of exogenous cholic acid when co-infused with DHCA. Phospholipid secretion declined to an undetectable amont and cholesterol declined to 10% of the base value by the end of the infusion. The reduction of biliary lipid secretion during DHCA infusion was attributed to the diminished secretion of endogenous bile acids. These data show that DHCA infusion induces choleresis associated with reduced secretion of endogenous and/or exogenous biliary components.

Although immaturity of the liver and synthesis of monohydroxy bile acids have been implicated as pathogenic factors in neonatal cholestasis, there is no direct evidence to show that these bile acids induce cholestasis in the newborn. In the present investigation, we compared the effects of lithocholic acid (LCA) injection on bile flow in suckling (2-week-old) and adult (12-week-old) guinea pigs. Bile flow was not modified by LCA in 2-week-old animals, but it was reduced by 50 to 80% in the adults, the decrease being dose-dependent. In the newborn, the injected LCA was mainly secreted in bile (greater than 90%), while in the adults it was distributed between the liver and bile. The percentage of biliary bile acids (as determined by gas-liquid chromatography) in the two groups was similar before and after LCA injection. Morphologic lesions characteristic of LCA-induced cholestasis were observed only in the adult guinea pigs. This study demonstrates that the newborn guinea pig is less susceptible to cholestasis induced by 90 to 180 mumoles per kg body weight of lithocholate and that, in the neonatal liver, there is no defect in the transport of this bile acid from blood to bile.