title: Di-n-butyl phthalate causes estrogenic effects in adult male Murray rainbowfish (Melanotaenia fluviatilis).
abstract: Phthalic acid esters (PAEs) are a class of synthetic industrial chemicals commonly found in the aquatic environment worldwide. PAEs have been recognised as anti-androgens in male mammals but little is known about their endocrine disrupting effects in fish. This study investigated the effects of 7-day exposures to nominal (measured) concentrations of 125 (62), 250 (140), 500 (230) and 1,000 (383) μg/L of di-n-butyl phthalate (DnBP) on the biomarkers of reproduction in adult male Murray River rainbowfish (Melanotaenia fluviatilis) using molecular, biochemical and histological endpoints. None of the tested concentrations of DnBP had any effect on survival or the vital body indices of the fish. The sizes of spermatogonia, Type A and B spermatocytes and spermatids were significantly smaller relative to the controls after treatment with DnBP. This was accompanied by a significant increase in the proportion of spermatogonia in fish treated with 250-1,000 μg/L of DnBP in comparison to the unexposed fish. At the end of the exposure period, the expressions of the transcripts for the androgen receptors α and β were significantly elevated in the livers of the fish treated with 500 and 1,000 μg/L of DnBP. In addition, there was also an increase in the circulating concentrations of vitellogenin in the plasma in the higher treatment groups. An induction in the activity of aromatase was noted in the brains of 1,000 μg/L DnBP-treated fish. This was accompanied by an increase in the hepatic expression of the genes (here and later, whenever the phrase gene expression is used as a synonym for gene transcription although it is acknowledged that it is also regulated, e.g., by translation, mRNA stability and protein stability) encoding for the oestrogen receptors α and β and choriogenin L. Collectively, an increase in the proportion of spermatogonia in the testes, the upregulation of the genes for the oestrogen receptors and choriogenin in the liver, an induction in the brain aromatase activity and the increase in the circulating levels of plasma vitellogenin suggest that continuous exposures for 7 days to sub-acute concentrations of DnBP can adversely affect the reproductive health of the male Murray rainbowfish by an estrogenic mode of action.
authors.affiliation: CSIRO Land and Water, PMB 2, Glen Osmond, Adelaide, SA 5064, Australia; School of Agriculture, Food and Wine, Waite Research Institute, PMB 1, The University of Adelaide, Adelaide, SA 5064, Australia. Electronic address: harpreet.bhatia@csiro.au.
authors.forename: Harpreet
authors.initials: H
authors.lastname: Bhatia
authors.affiliation: CSIRO Land and Water, PMB 2, Glen Osmond, Adelaide, SA 5064, Australia.
authors.forename: Anupama
authors.initials: A
authors.lastname: Kumar
authors.affiliation: Department of Bioenvironmental Science, Okazaki Institute for Integrative Bioscience, National Institute for Basic Biology, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan.
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Ogino
authors.affiliation: CSIRO Land and Water, PMB 2, Glen Osmond, Adelaide, SA 5064, Australia.
authors.forename: Adrienne
authors.initials: A
authors.lastname: Gregg
authors.affiliation: Office of Environment and Heritage, PMB 29, Lidcombe, NSW 1825, Australia.
authors.forename: John
authors.initials: J
authors.lastname: Chapman
authors.affiliation: CSIRO Land and Water, PMB 2, Glen Osmond, Adelaide, SA 5064, Australia; School of Agriculture, Food and Wine, Waite Research Institute, PMB 1, The University of Adelaide, Adelaide, SA 5064, Australia.
authors.forename: Mike J
authors.initials: MJ
authors.lastname: McLaughlin
authors.affiliation: Department of Bioenvironmental Science, Okazaki Institute for Integrative Bioscience, National Institute for Basic Biology, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan.
authors.forename: Taisen
authors.initials: T
authors.lastname: Iguchi
mesh_terms: D000818:Animals; D001141:Aromatase / Q000235:genetics; D003993:Dibutyl Phthalate / Q000633:toxicity*; D004967:Estrogens; D005786:Gene Expression Regulation / Q000187:drug effects; D008297:Male; D011960:Receptors, Estrogen / Q000235:genetics; D023701:Smegmamorpha / Q000502:physiology*; D013094:Spermatozoa / Q000187:drug effects*; D014819:Vitellogenins / Q000235:genetics; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D004967:Estrogens; D011960:Receptors, Estrogen; D014819:Vitellogenins; D014874:Water Pollutants, Chemical; D003993:Dibutyl Phthalate; D001141:Aromatase
keywords: Aromatase; Di-n-butyl phthalate; Receptors; Testis histopathology; Vitellogenin