<P> Quantitatively , the smooth endoplasmic reticulum of the liver cell is the principal organ of drug metabolism , although every biological tissue has some ability to metabolize drugs . Factors responsible for the liver 's contribution to drug metabolism include that it is a large organ , that it is the first organ perfused by chemicals absorbed in the gut , and that there are very high concentrations of most drug - metabolizing enzyme systems relative to other organs . If a drug is taken into the GI tract , where it enters hepatic circulation through the portal vein , it becomes well - metabolized and is said to show the first pass effect . </P>
<P> Quantitatively , the smooth endoplasmic reticulum of the liver cell is the principal organ of drug metabolism , although every biological tissue has some ability to metabolize drugs . Factors responsible for the liver 's contribution to drug metabolism include that it is a large organ , that it is the first organ perfused by chemicals absorbed in the gut , and that there are very high concentrations of most drug - metabolizing enzyme systems relative to other organs . If a drug is taken into the GI tract , where it enters hepatic circulation through the portal vein , it becomes well - metabolized and is said to show the first pass effect . </P>
the biotransformation or metabolism of a drug most often occurs in the
the biotransformation or metabolism of a drug most often occurs in the
smooth endoplasmic reticulum of the liver cell
smooth endoplasmic reticulum of the liver cell