Inhibition of tissue aryl hydrocarbon (benzo[a]pyrene) hydroxylase by 7,8-benzoflavone in birds

Abstract

1. Addition of 7,8-benzoflavone (7,8-BF) inhibited both hepatic and renal constitutive activity of aryl hydrocarbon (benzo[a]pyrene) hydroxylase in vitro for a number of avian species. Inhibition of hepatic benzo[a]pyrene hydroxylase was 70–94% in wild pigeon; 46–88% in homing pigeon; 85–93% in house crow; 18–53% in common kite; 56–86% in cattle egret; and for the renal enzyme was 43–84, 52–88, 18–73 and 13–48% respectively.

2. 3-Methylcholanthrene treatment of homing pigeons resulted in the induction of liver and kidney benzo[a]pyrene hydroxylase activity. Induced enzyme activity was also significantly inhibited by 7,8-BF.