title: Effects of nonylphenol on the gonadal differentiation of the hermaphroditic fish, Rivulus marmoratus.
abstract: Nonylphenol (NP) is an estrogenic degradation product of alkylphenol polyethoxylate surfactants. In this study, the effects of NP on gonadal differentiation and development in Rivulus marmoratus (Osteichthyes, Cyprinodontiformes), a self-fertilizing, hermaphroditic species, were examined. Starting at hatching, fish were exposed to 150 or 300 microg 1(-1) NP (nominal concentrations) in a static system with daily renewal. The measured concentration of NP in the test water decreased rapidly; half-life was 8.0 h. After 60 d of exposure to NP, fish were kept in uncontaminated water for 20 d and were then preserved for histological examination. No fish exposed to 300 microg l(-1) NP (N=8) and only two of nine fish exposed to 150 microg l(-1) NP developed testicular tissue, compared with nine of 13 water-control fish and five of nine solvent-control fish. Oogenesis was also significantly inhibited by NP. None of the fish exposed to 300 microg l(-1) and only two of nine fish exposed to 150 microg l(-1) NP had vitellogenic oocytes, compared with seven of 11 water-control fish (not including males) and six of nine solvent-control fish. Dysplasia of the gonadal lumen also occurred in fish exposed to 300 microg l(-1) NP. These changes, including testicular agenesis, have not been previously reported in fish exposed to NP.
authors.affiliation: Southeastern Cooperative Fish Disease Project, Department of Fisheries and Allied Aquacultures, Auburn University, AL 36849, USA.
authors.forename: Jennifer N
authors.initials: JN
authors.lastname: Tanaka
authors.forename: John M
authors.initials: JM
authors.lastname: Grizzle
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D004781:Environmental Exposure; D005260:Female; D005399:Fishes / Q000254:growth & development*; D057850:Hermaphroditic Organisms; D008297:Male; D010053:Ovary / Q000187:drug effects / Q000254:growth & development*; D010636:Phenols / Q000009:adverse effects*; D019849:Sex Determination Processes; D012733:Sex Differentiation / Q000187:drug effects*; D013737:Testis / Q000187:drug effects / Q000254:growth & development*; D014818:Vitellogenesis / Q000187:drug effects; D014874:Water Pollutants, Chemical / Q000009:adverse effects*
chemical_list: D010636:Phenols; D014874:Water Pollutants, Chemical; C025256:nonylphenol