title: Evaluation of 4-nonylphenol in vivo exposure in Dreissena polymorpha: Bioaccumulation, steroid levels and oxidative stress.
abstract: Nonylphenol (NP) represents the most critical metabolite of alkylphenols (APs) and alkylphenol ethoxylates (APEs), non-ionic surfactants widely used in the formulation of domestic and industrial products. On the basis of in vitro and in vivo animal studies 4-nonylphenol (4-NP) is considered an endocrine disrupting chemical (EDC). The evidence to date indicates that mollusks are able to synthesize sex steroids from the precursor cholesterol and their endocrine pathways are theoretically susceptible to disruption. The aim of this study was to investigate the endocrine modulating potency of 4-NP in the freshwater mussel Dreissena polymorpha by looking at endogenous steroid levels in control and exposed individuals. 4-NP bioaccumulation in mussels tissues and alterations in the activity of enzymes related both to oxidative stress (catalase - CAT- and glutathione peroxidase - GPX-) and phase II metabolism (glutathione-S-transferase - GST-) were also assessed. The results highlighted a build-up of 4-NP in exposed mussels and an overall decrease of 17-beta-estradiol and testosterone levels. On the other hand this chemical at the tested concentrations does not interfere with the antioxidant defense mechanisms in D. polymorpha. The mechanisms by which 4-NP alter steroids levels are unknown and require more in-depth investigations.
authors.affiliation: Department of Biology, University of Milan, via Celoria 33, 20133 Milan, Italy. consuelo.riva@unimi.it
authors.forename: Consuelo
authors.initials: C
authors.lastname: Riva
authors.forename: Cinta
authors.initials: C
authors.lastname: Porte
authors.forename: Andrea
authors.initials: A
authors.lastname: Binelli
authors.forename: Alfredo
authors.initials: A
authors.lastname: Provini
mesh_terms: D000818:Animals; D002374:Catalase / Q000378:metabolism; D049875:Dreissena / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D052244:Endocrine Disruptors / Q000378:metabolism / Q000633:toxicity*; D004958:Estradiol / Q000378:metabolism*; D005979:Glutathione Peroxidase / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D018384:Oxidative Stress; D010636:Phenols / Q000378:metabolism / Q000633:toxicity*; D013739:Testosterone / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000378:metabolism / Q000633:toxicity
chemical_list: D052244:Endocrine Disruptors; D010636:Phenols; D014874:Water Pollutants, Chemical; D013739:Testosterone; D004958:Estradiol; D002374:Catalase; D005979:Glutathione Peroxidase; D005982:Glutathione Transferase; C041594:4-nonylphenol