Cytochrome P450 of small intestinal epithelial cells. Immunochemical characterization of the increase in cytochrome P450 caused by phenobarbital

Gastroenterology. 1985 Feb;88(2):458-67. doi: 10.1016/0016-5085(85)90507-4.


We have studied total cytochrome P450 and the major form of cytochrome P450 increased by phenobarbital in small intestinal epithelial cells and livers of male Sprague-Dawley rats. Using an improved method for preparing microsomes from intestinal epithelial cells, we find that concentrations of total cytochrome P450 in intestinal cell microsomes are 10% of those in liver microsomes, and that this percentage is unchanged after phenobarbital treatment. In untreated rats, less than 5% of total cytochrome P450 of liver or intestinal epithelium is the form induced by phenobarbital, as measured by rocket immunoelectrophoresis. In phenobarbital-treated rats, the major phenobarbital-induced form accounts for approximately 50% of the total in both organs. In the small intestine of phenobarbital-treated rats, the concentrations of total cytochrome P450 and of the major phenobarbital-induced form increase concurrently as epithelial cells mature from crypt to upper villus. Concentrations of total cytochrome P450 and of the major phenobarbital-induced form in the proximal two-thirds of the rat small intestine are twofold higher than in the distal third. Immunoblotting performed with a monoclonal antibody to the major phenobarbital-induced form of cytochrome P450 from rat liver revealed a subtle difference between this form in liver and intestine.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Antibodies, Monoclonal / immunology
  • Cytochrome P-450 Enzyme System / analysis*
  • Cytochrome P-450 Enzyme System / immunology
  • Epithelium
  • Immunoelectrophoresis
  • Intestine, Small / analysis
  • Intestine, Small / drug effects*
  • Intestine, Small / immunology
  • Liver / analysis
  • Liver / drug effects
  • Liver / immunology
  • Male
  • Microsomes / analysis
  • Microsomes / drug effects
  • Microsomes / immunology
  • Phenobarbital / pharmacology*
  • Rats
  • Rats, Inbred Strains


  • Antibodies, Monoclonal
  • Cytochrome P-450 Enzyme System
  • Phenobarbital