Bile acid transport in the anhepatic rat

Hepatocyte dysfunction eventually results in the loss of canalicular bile formation. Without canalicular flow, intestinal bile acid may originate from plasma by reverse transport. Anhepatic rats with preserved intestinal function permit evaluation of such transport. In the present study, plasma taurocholate clearance was markedly decreased in anhepatic rats. The relative proportion of free cholate increased with time. Peripheral tissues contained virtually only cleared taurocholate, but the intestinal contents were mainly free cholate. This indicates the intestinal contents as the source of the plasma cholate and shows an equilibrium between intestinal and plasma bile acid even without bile flow. The enteral administration of an anion exchange resin to anhepatic rats increased intestinal bile acid recovery and decreased the bile acid recovery in tissue. Plasma bile acid concentration was decreased and fractional loss increased threefold, confirming the anhepatic plasma-intestine bile acid equilibrium. However, the enhanced plasma clearance produced by the resin was less than 1% of the fractional loss found in the intact rat. These data show a very limited bile acid flux between intestine and plasma without bile flow, which could be modestly influenced by an intestinal bile acid sequestrant.