These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Effect of dietary fat on the induction of hepatic microsomal cytochrome P450 isozymes by phenobarbital.
    Author: Kim HJ, Choi ES, Wade AE.
    Journal: Biochem Pharmacol; 1990 May 01; 39(9):1423-30. PubMed ID: 2334442.
    Abstract:
    Dietary polyunsaturated fatty acid is needed for optimal induction of cytochrome P450. In this study we quantitated cytochrome P450 hemoproteins in male Sprague-Dawley rats that were starved for 36 hr and then refed a fat-free diet (FF) or a diet containing 20% corn oil for 4 days. Some received phenobarbital (Pb) sodium (80 mg/kg, i.p., daily) for 3 days prior to decapitation. Microsomal cytochrome P450 levels were measured by carbon monoxide binding spectra, and the P450 isozymes separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis were quantitated by gel scanner. Cytochrome P450 PB-B was quantitated by a Western blot technique. Rats fed FF diet and administered Pb had only 21% more microsomal P450 than non-induced controls, whereas rats fed 20% corn oil diet had 59% more P450 and Pb-treated rats fed 20% corn oil diet had 181% more P450 than FF controls. Analysis of gels showed 32, 59 and 124% more P450 protein, respectively, in FF Pb, corn oil control or corn oil Pb groups than in FF controls. Cytochrome P450 PB-B was not detected in non-induced groups, but quantitation by Western blot yielded 0.32 and 0.70 nmol/mg protein, respectively, in FF Pb and corn oil Pb groups. Our findings suggest that deprivation of dietary fat reduces the total amount of cytochrome P450 hemoprotein and its inducibility by Pb through decreased P450 hemoprotein synthesis. The limiting factor(s) restricting synthesis of new cytochrome P450 hemoproteins in rats refed a diet devoid of fat may be the inability to respond to the inducer (Pb) or the paucity of utilizable fatty acids needed for synthesis of the phospholipid matrix of the endoplasmic reticulum necessary for the support and proper juxtapositioning of these protein molecules.
    [Abstract] [Full Text] [Related] [New Search]