title: Fertilization success and sexual behavior in male medaka, Oryzias latipes, exposed to tributyltin.
abstract: We evaluated the effects of tributyltin (TBT), polychlorinated biphenyls (PCBs), and a mixture of TBT and PCBs on reproduction, gonadal histology, and sexual behavior in Japanese medaka (Oryzias latipes). We administered TBT (1 microg g(-1) body weight [b.w.] daily), PCBs (1 microg g(-1) b.w. daily), or both to medaka for 3 weeks. We assessed reproductive success during week 3 and the sexual behavior of male medaka after the exposure period. Fertilization success was significantly decreased in groups that received TBT. The profiles of fertility developed a bimodal distribution in the TBT and TBT+PCBs groups, and the numbers of males that performed "following" and "dancing" were significantly decreased in the TBT+PCBs group. The frequency of "dancing" also decreased after treatment with TBT, whereas fish that received PCBs only showed no difference in sexual behavior. Testes that had oocytes showed normal spermatogenesis, even though two of the five males treated with TBT+PCBs had some indication of testis-ova, which did not occur in any other group. Our results indicate that TBT, but not PCBs, affects sexual behavior and reproduction in medaka.
authors.affiliation: Laboratory of Marine Environmental Science, Department of Bioscience and Biotechnology, Division of Bioresource and Bioenvironmental Sciences, Graduate School, Kyushu University, Hakozaki 6-10-1, Higashi-ku, Fukuoka 812-8581, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Nakayama
authors.forename: Yuji
authors.initials: Y
authors.lastname: Oshima
authors.forename: Tomomi
authors.initials: T
authors.lastname: Yamaguchi
authors.forename: Yukinari
authors.initials: Y
authors.lastname: Tsuruda
authors.forename: Ik Joon
authors.initials: IJ
authors.lastname: Kang
authors.forename: Makito
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Nobuyoshi
authors.initials: N
authors.lastname: Imada
authors.forename: Tsuneo
authors.initials: T
authors.lastname: Honjo
mesh_terms: D000818:Animals; D004032:Diet; D005260:Female; D005298:Fertility / Q000187:drug effects* / Q000502:physiology; D006066:Gonads / Q000187:drug effects*; D006652:Histological Techniques; D008297:Male; D009990:Oryzias / Q000502:physiology*; D011078:Polychlorinated Biphenyls / Q000633:toxicity*; D012726:Sexual Behavior, Animal / Q000187:drug effects* / Q000502:physiology; D014220:Trialkyltin Compounds / Q000008:administration & dosage / Q000633:toxicity*
chemical_list: D014220:Trialkyltin Compounds; C011559:tributyltin; D011078:Polychlorinated Biphenyls