Metabolic Changes Associated With 17α-Ethinylestradiol- Exposure In The Pregnant Teleost Zoarces Viviparus (L)
Abstract: Females of the eelpout Zoarces viviparus were exposed in the ambient seawater to the synthetic estrogen 17α-ethinylestradiol at different doses, 5, 10, 25, 50, 500 ng/L during early pregnancy and the effect on the maternal metabolism was studied. A significant dose-related increase in the level of calcium and the yolkprecursor-protein vitellogenin was observed in plasma of the exposed motherfish. The increased synthesis of vitellogenin could also be observed in the liver of the exposed motherfish by PCR and indirectly by the increase in the hepato-somatic index. No significant effects were observed in the concentration of glucose in plasma; the concentrations of amino acids in plasma, however, showed a significant decrease in the groups exposed to the higher doses of EE2. A general decrease in plasma osmolarity and chloride-concentrations were found in the exposed groups compared to controls.
A dose-related decrease was observed in the activity of glutamate pyruvate-transaminase (GPT). The EE2- induced changes in the hepatic activity of the glycolytic enzyme pyruvate kinase (PK) and the gluconeogenetic enzyme PEPCK as well as of glucose-6-phosphate dehydrogenase (G6PDH), an indicator for oxidative stress response, were less consistent. The activity of these 3 enzymes was observed to decrease significantly when expressed per unit liver wet weight but to increase in the high dose groups when activity was expressed normalized to the hepatosomatic index.
Key words: xenoestrogens, exposure, metabolism, eelpout, viviparous teleost