title: Low-dose exposure to alkylphenols adversely affects the sexual development of Atlantic cod (Gadus morhua): acceleration of the onset of puberty and delayed seasonal gonad development in mature female cod.
abstract: Produced water (PW), a by-product of the oil-production process, contains large amount of alkylphenols (APs) and other harmful oil compounds. In the last 20 years, there have been increasing concerns regarding the environmental impact of large increases in the amounts of PW released into the North Sea. We have previously shown that low levels of APs can induce disruption of the endocrine and reproductive systems of Atlantic cod (Gadus morhua). The aims of this follow-up study were to: (i) identify the lowest observable effect concentration of APs; (ii) study the effects of exposure to real PW, obtained from a North Sea oil-production platform; and (iii) study the biological mechanism of endocrine disruption in female cod. Fish were fed with feed paste containing several concentrations of four different APs (4-tert-butylphenol, 4-n-pentylphenol, 4-n-hexylphenol and 4-n-heptylphenol) or real PW for 20 weeks throughout the normal period of vitellogenesis in Atlantic cod from October to January. Male and female cod, exposed to AP and PW, were compared to unexposed fish and to fish fed paste containing 17β-oestradiol (E(2)). Approximately 60% of the females and 96% of the males in the unexposed groups were mature at the end of the experiment. Our results show that exposure to APs and E(2) have different effects depending on the developmental stage of the fish. We observed that juvenile females are advanced into puberty and maturation, while gonad development was delayed in both maturing females and males. The AP-exposed groups contained increased numbers of mature females, and significant differences between the untreated group and the AP-treated groups were seen down to a dose of 4 μg AP/kg body weight. In the high-dose AP and the E(2) exposed groups, all females matured and no juveniles were seen. These results suggest that AP-exposure can affect the timing of the onset of puberty in fish even at extremely low concentrations. Importantly, similar effects were not seen in the fish that were exposed to real PW.
authors: Institute of Marine Research, Bergen, Norway. sonnich.meier@imr.no
authors: Sonnich
authors: S
authors: Meier
authors: H Craig
authors: HC
authors: Morton
authors: Eva
authors: E
authors: Andersson
authors: Audrey J
authors: AJ
authors: Geffen
authors: Geir Lasse
authors: GL
authors: Taranger
authors: Marita
authors: M
authors: Larsen
authors: Marianne
authors: M
authors: Petersen
authors: Rune
authors: R
authors: Djurhuus
authors: Jarle
authors: J
authors: Klungsøyr
authors: Asbjørn
authors: A
authors: Svardal
mesh_terms: D000818:Animals; D001141:Aromatase / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D052244:Endocrine Disruptors / Q000633:toxicity; D004703:Endocrine System / Q000187:drug effects / Q000378:metabolism; D004958:Estradiol / Q000097:blood; D005260:Female; D005640:Follicle Stimulating Hormone / Q000235:genetics / Q000378:metabolism; D048389:Gadus morhua; D007986:Luteinizing Hormone / Q000235:genetics / Q000378:metabolism; D008297:Male; D010053:Ovary / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D010636:Phenols / Q000633:toxicity*; D012333:RNA, Messenger / Q000378:metabolism; D012621:Seasons; D012744:Sex Ratio; D046468:Sexual Development / Q000187:drug effects*; D012741:Sexual Maturation / Q000187:drug effects; D013739:Testosterone / Q000097:blood; D014819:Vitellogenins / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D052244:Endocrine Disruptors; D010636:Phenols; D012333:RNA, Messenger; D014819:Vitellogenins; D014874:Water Pollutants, Chemical; D013739:Testosterone; D004958:Estradiol; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D001141:Aromatase