title: Effects of 17beta-estradiol and 4-nonylphenol on osmoregulation and hepatic enzymes in gilthead sea bream (Sparus auratus).
abstract: Sexually immature Sparus auratus were injected intraperitoneally with coconut oil either alone (control) or containing 17beta-estradiol (E2, 10 microg/g body mass) or 4-nonyphenol (4-NP, 100 and 200 microg/g body mass) and sampled 10 days later. Gill and kidney Na(+),K(+)-ATPase activities, plasma levels of E2 and cortisol, plasma osmolites (osmolality, sodium and chloride) and metabolites (glucose, lactate, proteins and triglycerides) were examined. Livers were used for measuring hepatosomatic index (HSI) and determinations of the activities of antioxidant defences catalase (CAT) and total glutatione peroxidase (t-GPX), the CYP1A-dependent, 7-ethoxyresorufin O-deethylase (EROD) and glutathione S-transferase (GST). HSI and plasma levels of E2 were significantly increased in E2 -treated fish. E2 treatment enhanced plasma osmolality, glucose, triglycerides and proteins, but had no effect on plasma cortisol, and gill and kidney Na(+),K(+)-ATPase activities. Hepatic activities of EROD, GST and CAT were significantly decreased after E2 administration, whereas t-GPX remained unaffected. Treatment with 200 microg/g 4-NP caused a slight increase in plasma E2 relative to the control group. Plasma glucose and protein levels were not affected by 4-NP, while triglycerides were increased. Fish treated with the higher dose of 4-NP displayed a clear reduction in kidney Na(+),K(+)-ATPase activity, together with increases in plasma osmolality, relative to the control group. High 4-NP also caused a significant decrease in EROD and an increase in GST activity. Our results confirm the regulation of the natural estrogen E2 and the weak xenoestrogen 4-NP on osmoregulation and biotransformation enzymes in a partially similar manner. The actions of xenoestrogens on critical physiological processes may have an ecological significance as it can reduce adaptability and capacity to metabolise xenobiotics under stressful conditions.
authors.affiliation: Departamento Biología, Facultad Ciencias del Mar y Ambientales, Universidad de Cádiz, 11510 Puerto Real, Cádiz, Spain.
authors.forename: Erkuden Pérez
authors.initials: EP
authors.lastname: Carrera
authors.forename: Angel
authors.initials: A
authors.lastname: García-López
authors.forename: María del Pilar
authors.initials: Mdel P
authors.lastname: Martín del Río
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Martínez-Rodríguez
authors.forename: Montserrat
authors.initials: M
authors.lastname: Solé
authors.forename: Juan Miguel
authors.initials: JM
authors.lastname: Mancera
mesh_terms: D000818:Animals; D002374:Catalase / Q000378:metabolism; D019363:Cytochrome P-450 CYP1A1 / Q000378:metabolism; D004958:Estradiol / Q000097:blood / Q000493:pharmacokinetics / Q000633:toxicity*; D004967:Estrogens / Q000097:blood / Q000493:pharmacokinetics / Q000633:toxicity*; D005880:Gills / Q000187:drug effects / Q000201:enzymology; D005979:Glutathione Peroxidase / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D006706:Homeostasis; D007668:Kidney / Q000187:drug effects / Q000201:enzymology; D008099:Liver / Q000187:drug effects / Q000201:enzymology; D008297:Male; D009994:Osmolar Concentration; D010636:Phenols / Q000633:toxicity*; D021541:Sea Bream / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism
chemical_list: D004967:Estrogens; D010636:Phenols; D004958:Estradiol; C025256:nonylphenol; D002374:Catalase; D005979:Glutathione Peroxidase; D019363:Cytochrome P-450 CYP1A1; D005982:Glutathione Transferase; D000254:Sodium-Potassium-Exchanging ATPase