Effects of Corynebacterium parvum vaccine on drug metabolism in the mouse.

Mice of the CBA strain were given a single intraperitoneal injection of C. parvum vaccine at 50 mg/m2. There followed a progressive increase in liver weight and in the duration of hexobarbitone sleeping time, accompanied by a marked decrease in liver microsomal protein and in cytochrome P-450/mg microsomal protein. That is to say, content of cytochrome P-450 was reduced out of proportion to the apparent loss of endoplasmic reticulum. These changes were paralleled by decreases in microsomal O-demethylation of p-nitroanisole and glucuronide formation with o-aminophenol measured in vitro; they were most marked at 13-14 days after dosing; they then slowly returned to control levels which they reached 20-30 days later. Changes in the dose of vaccine showed that the increase in liver weight and in hexobarbitone sleeping time were significant at 3.5 mg/m2, but that the decrease in the activities measured in vitro were not significant below 35 mg/m2.