Microsomal enzyme activity, glutathione S-transferase-placental form expression, cell proliferation, and vitamin a stores in livers of rats consuming Great Lakes Salmon

Male and female Sprague-Dawley rats were fed diets incorporating lyophilized chinook salmon obtained from Lake Ontario and Lake Huron. After 70 days, females were bred and the progeny (F1) were reared on the same fish-based diets as the adults (F0). After 78-133 days on the diets, males and females of both generations were sacrificed and hepatic microsomal enzyme activities determined, along with glutathione S-transferase-placental form (GSTP) expression and hepatic cellular proliferation. Hepatic P450 enzyme activities (MROD, EROD, PROD, BROD, and aminopyrine) were increased significantly by fish diets from both sources. Increases in hepatic enzyme activity were greatest for fish caught from Lake Ontario and reflected the total levels of organochlorine contaminants in the fish. GSTP and cell proliferation rates did not show any diet-related or dose-related changes. Vitamin A stores were analyzed as the concentration of liver retinyl palmitate. In rats receiving the highest TEQ dose (i.e., 20% Lake Ontario fish diet), vitamin A stores were significantly lower in F0 adults, F1 weanlings, and F1 adult females.