Effect of feeding irradiated fish on the drug-metabolizing liver enzymes in rats

Abstract

The activity of drug-metabolizing liver enzymes was studied by physiological, biochemical, and pharmacological tests in male Wistar rats fed irradiated fish for 3, 7, 21, and 42 days. Animals receiving food containing 45% 200-krad-irradiated fish showed a 20% higher growth rate than control animals. The liver microsomal protein content was 20% higher than in control animals, while the cytochrome P -450 concentration was unchanged. The aminopyrine N -demethylating and aniline-hydroxylating activities were slightly decreased. The inhibition of the microsomal enzymatic activity was more evident in the pharmacological test: The hexobarbital sleeping time was up to 30–40% longer in animals fed irradiated fish than in control animals. These results are compared to those of a group of 50-ppm DDT-treated rats, which were used as a positive reference for an induction effect. In conclusion, no significant enzyme induction effect was observed in rats fed irradiated fish. On the contrary, the inhibition effect observed in the microsomal enzymes might lead to a potentiation of the action of certain drugs.