EFFECT OF TRAINING AND ANABOLIC-ANDROGENIC STEROIDS ON DRUG-METABOLISM IN RAT-LIVER

The effects of anabolic-androgenic steroid administration and exercise training on various aspects of hepatic function were investigated in sedentary and trained (treadmill for 12 wk) male and female rats treat ed orally with fluoxymesterone or methylandrostanolone (2 mg.kg-1 body weight, 5 d.wk-1 for 8 wk). The mean values of serum alanine aminotra nsferase, aspartate aminotransferase, alkaline phosphatase, total and direct bilirubin, and total- and high-density lipoprotein-cholesterol remained within normal range in all groups of male animals. The same i s true for female rats, except for an increase in alkaline phosphatase activity in the steroid-treated groups. Hepatic microsomal aniline p- hydroxylase activity was reduced in male and increased in female rats by either steroid, whereas no significant effect was detected on 7-eth oxycoumarin deethylase activity. The levels of cytochrome P-450 and cy tochrome b5 were markedly decreased by the anabolic-androgenic steroid treatment in male rat microsomes, but neither the steroid administrat ion nor exercise training induced significant changes in the cytochrom e levels of female rat livers. Taking into account the significant inc rease in microsomal protein yield elicited by fluoxymesterone or methy landrostanolone treatment both in males and females, it is noteworthy that the total monooxygenase activities and cytochrome P-450 content, expressed on a per gram liver basis, were significantly increased in f emale whereas they were apparently unchanged in male rats. In conclusi on, the present data show that the prolonged ingestion of high doses o f anabolic-androgenic steroids, either with or without concurrent exer cise training, can modify in a sex-dependent manner the capacity of ra t liver to metabolize drugs without affecting classical serum indicato rs of hepatic function.