Hepatic transport of bile salt and bile composition following total parenteral nutrition with and without lipid emulsion in the rat.

The effect of total parenteral nutrition (TPN) on bile flow and composition and on hepatic bile acid transport maximum (Tm) and bile salt-independent bile flow (BSIF) was studied in the rat following seven days TPN containing 33% calories from Intralipid (IL) or Liposyn (LP) or 0% calories from lipid. All TPN regimes markedly reduced bile flow. In no case did TPN cause an increase in bile cholesterol concentration or saturation relative to bile acid and phospholipid. Bile acid Tm was reduced in rats receiving either 0% lipid or 33% IL; BSIF was reduced only in the 0% lipid group. Rats receiving 33% LP had a higher bile flow than the other TPN regimes while bile acid Tm and BSIF were similar to controls. It is proposed that in established TPN, bile flow is reduced largely as a result of decreased hepatic bile acid excretion. In the rat, TPN has no deleterious effect on the molar concentration of cholesterol, phospholipid or bile acid in bile secreted by the hepatocyte. The significant differences between the effect of the two lipid emulsions on hepatobiliary function require further study.