Drug metabolizing enzymes in the ostrich (Struthio camelus): comparison with the chicken and the rat.

The activities of selected hepatic and renal drug-metabolizing enzymes of the ostrich, chicken and rats were compared. The concentration of glutathione in the liver and kidneys of the avian species was significantly lower than in the rat. The activity of ostrich hepatic glutathione S-transferase was 2-fold higher than that of the chicken and the rat and the renal glutathione S-transferase of the ostrich was 10 times higher than that of the rat. The activity of ostrich hepatic UDP-glucuronyl transferase was significantly lower than that of the rat. The activities of hepatic cytochrome P450 1A and 2B1/2 as measured by the dealkylation of ethoxy- and methoxyresorufin, respectively, were higher int he avian species than the rat; no difference was noticed in the activity of aniline hydroxylase. The results show that the activity of ostrich drug-metabolizing enzyme system is quantitatively different from the rat and in many cases also from the chicken.