Cholestasis and total parenteral nutrition: in vivo studies on dogs

The effect of total parenteral nutrition (TPN) on bile formation was evaluated in 10 studies performed on three adult dogs. The bile duct was directly cannulated via a Thomas cannula while bile salt secretion was maintained by intravenous [14C]taurocholic acid infusion. After a 1.5-h basal period, either an amino acid solution (2.5% Travasol) with 10% glucose, or a lipid emulsion (10% Intralipid) was added intravenously for 2 h, followed by a second control period. The amino acid-glucose solution resulted in a significant (p less than 0.05) increase in bile flow which rose (+33%) while bile salt secretion increased transiently (+11%) and then returned to basal levels. The specific activity of taurocholate secreted did not decrease during the amino acid-glucose infusion, indicating that the unexpected increase in bile salt secretion was mainly due to a washout of the biliary tree rather than to enhanced synthesis. Cholesterol, phospholipid, and bilirubin outputs did not change significantly. Intralipid had no effect on bile flow or solute secretion. Thus, short-term TPN therapy with amino acids and glucose had no cholestatic effect in dogs, but rather produces a transient choleresis which is largely independent of bile salts.