Hepatic mixed-function oxidase activities of wild pigeons.

Hepatic mixed-function oxidase activities of wild pigeons were determined and compared with those of rat to assess the apparent differences in avian and mammalian drug metabolism. Aminopyrine N-demethylase, benzphetamine N-demethylase, ethylmorphine N-demethylase, aniline hydroxylase, NADPH-cytochrome c reductase, glutathione S-transferase activities and cytochrome P-450 levels in pigeon liver were 30-80% lower than the corresponding activities in rat liver. p-Nitroanisole O-demethylase activity in pigeon liver was similar to that of rat liver. Wild pigeon-liver benzo[a]pyrene hydroxylase activity was approx. five times higher than that in the rat. Pigeons did not reveal any noticeable sex differences in mixed-function oxidase activities. Administration of 3-methylcholanthrene and phenobarbital to pigeons resulted in the induction of demethylase and benzo[a]pyrene hydroxylase activities and in cytochrome P-450 levels.