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.