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FASTING FOR LESS THAN 24 H INDUCES CYTOCHROME P450 2E1 AND 2B1/2ACTIVITIES IN RATS
Citation:
Brown, B., J. Allis, J. Simmons, AND D. House. FASTING FOR LESS THAN 24 H INDUCES CYTOCHROME P450 2E1 AND 2B1/2ACTIVITIES IN RATS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-96/060.
Description:
Cytochrome p450 (CYP) 2E1 activity is induced after 24hr of fasting but no information is available for shorter fasting periods. e investigated the induction of CYP 2E1 in rats during the first 24 hours of food deprivation by examining marker activities for CYP isozymes 2b 1/2 and 1A1 as well as 2E1. oung adult male F344 rats were deprived of feed for either 0,8,16, or 24hr. iver microsomes were prepared and analyzed for the following enzyme activities: p-nitrophenol hydroxylase (pnp) for CYP 2E1, pentoxyresorufin-O-dealkylase (PROD) for CYP 2b 1/2 and ethoxyresorufin-O-deethylase (EROD) for CYP 1a1. fter each deprivation interval, the specific activities (per mg icrosomal protein) for pnp and prod increased. he specific activity of rod remained unchanged over the course of the experiment. hen measured on a whole organ basis, the PNP and PROD activities increased at 16hr with PNP also up at 24hr, while erod activity decreased at 24hr and total microsomal protein decreased successively at each time. he results are consistent with an induction of CYP 2E1 and CYP 2b 1/2 activities after as little as 8hr of fasting.