Weighing between 1,400 and 1,600 gm in the adult, the liver is the largest internal organ in the human body. Its rich blood supply originates from two separate sources, the hepatic artery and the portal vein, the latter draining all the organs of the digestive tract. The liver exhibits a unique cellular architecture that permits blood to percolate through hepatic parenchyma, constantly exposing the hepatocyte to a variety of endogenous and exogenous substances. It also possesses the capacity to excrete certain of these substances into bile. Because of these characteristics, the human liver is both the major site of drug metabolism1 and the most common location of distant metastases from a variety of malignant tumors.
The hepatocyte contains enzymes that oxidize and conjugate chemical substances, modifying their pharmacologic characteristics and increasing their excretability in bile and urine. These enzymes are located primarily in the smooth endoplasmic reticulum, an interconnecting
LaRusso NF. Hepatic Drug Metabolism and Malignancy. JAMA. 1976;236(14):1612–1613. doi:10.1001/jama.1976.03270150046035