Effects of levels of feed restriction on in vivo and in vitro alterations in drug metabolism and associated enzymes.

The objective of this study was to determine if 15% and 30% feed restriction would enhance drug metabolism similar to that caused by 45% feed restriction. Four groups of weanling male Sprague-Dawley rats were subjected to 0%, 15%, 30%, and 45% feed restriction for 28 days. Feed restriction of 45% significantly enhanced hepatic DNA, microsomal protein, cytochrome P-450, aniline hydroxylase, p-chloromethylaniline-N-demethylase, and decreased hexobarbital sleeping time. The feed restriction of 15% and 30% did not significantly alter the above parameters of drug metabolism. The activities of NADPH-generating enzymes were enhanced by all levels of feed restriction. Thus it is concluded that 15% and 30% feed restriction did not enhance in vivo or in vitro drug metabolism to the extent enhanced by 45% restriction for the same length of time.