Biliary and Fecal Drug Excretion

The hepatocyte is the major cell involved in the metabolism & excretion of foreign materials (xenobiotics). These materials are taken up across the basolateral membrane by (often sodium-dependent) active transport proteins. On the sinusoidal plasma membrane, there are also several efflux transporters, principally the multidrug receptor (MDR) proteins. Inside the hepatocyte they may undergo phase I or phase II biotransformation reactions before being targeted for excretion, again by active transport, across the canalicular membrane into bile & expulsion via the intestine. Unlike bile acids, there is little intestinal re-absorption of these xenobiotics.