The effect of oral phenobarbitone on hepatic microsomal cytochrome P-450 and demethylation activity in rats fed normal and low protein diets

Abstract

The use of oral phenobarbitone to stimulate microsomal hydroxylation is described. A 0.1% solution of sodium phenobarbitone instead of normal drinking water causes maximal stimulation of enzyme activity and an increase in cytochrome P-450, of 7-fold over controls; there are also increases in liver weight and microsomal protein. The time course of this stimulation is found to be similar to that after injection of phenobarbitone. Feeding a 3% casein diet causes a fall in cytochrome P-450. When rats fed a low protein diet are given phenobarbitone, the level of P-450 rises, but is still only a quarter of that found in phenobarbitone treated rats given a stock diet. © 1969.