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.

ß-carotene and retinoids in eggs of Great Blue Herons (Ardea herodias) in relation to St Lawrence River contamination.

: The potential use of retinoids and ß-carotene as biomarkers in the eggs of the Great Blue Heron was investigated. In the spring of 1991, 65 eggs were collected from nine heronries (seven along the St Lawrence River and two reference sites). A method was specifically developed for the extraction and analysis of ß-carotene and the retinoids in heron egg yolks by reversed-phase HPLC. When results were expressed either as the molar ratio of retinol: retinyl palmitate or as retinyl palmitate concentration, significant differences were found between colonies; however, retinyl palmitate concentration was deemed the better biomarker because it was not significantly influenced by embryonic stage of development. Retinyl palmitate concentrations in freshwater colonies were negatively related to PCB congeners Nos 105 and 118 as well as their TCDD-EQ values (p < 0.02, r (2)=0.78). Egg tetrachloro-mono-ortho biphenyl concentrations were also negatively related to retinyl palmitate (p < 0.005, r (2)=0.90). With the exception of the two mono-ortho co-planar congeners detected in the present study, the contamination levels found in heron eggs were well below those found for other bird species in the Great Lakes area and, so far, no detrimental effects have been reported in Great Blue Heron populations in Quebec. These results suggest that retinyl palmitate may be useful as a sensitive and non-invasive biomarker for monitoring organochlorine contaminant effects in the Great Blue Heron in freshwater sites.