title: Possible involvement of organic anion transporting polypeptide 1c1 in the photoperiodic response of gonads in birds.
abstract: The photoperiodic response of the gonads requires T3, which is generated photoperiodically from T4 by type 2 iodothyronine deiodinase in the hypothalamus. Although thyroid hormones were long thought to traverse the plasma membrane by passive diffusion due to their lipophilic nature, it is now known that several organic anion transporting polypeptides (Oatp) transport thyroid hormones into target cells. In this study, we have used database searches to isolate DNA sequences encoding members of the chicken Oatp family and constructed a molecular phylogenetic tree. Comprehensive expression analyses using in situ hybridization revealed strong expression of cOatp1c1 and weak expression of cOatp1b1 in the ventro-lateral walls of basal tuberal hypothalamus, whereas expression of four genes (cOatp1a1, cOatp1b1, cOatp1c1, and cOatp3a2) was observed in the choroid plexus. Expression levels of all these genes in both regions were not different between short-day and long-day conditions. Functional expression of cOatp1c1 in Chinese hamster ovary cells revealed that cOatp1c1 is a highly specific transporter for T4 with an apparent Km of 6.8 nm and a Vmax of 1.50 pmol per milligram of protein per minute. These results suggest that cOatp1c1 could be involved in the thyroxine transport necessary for the avian photoperiodic response of the gonads.
authors.affiliation: Division of Biomodeling, Graduate School of Bioagricultural Sciences, and Institute for Advanced Research, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Nakao
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Takagi
authors.forename: Masayuki
authors.initials: M
authors.lastname: Iigo
authors.forename: Toshiro
authors.initials: T
authors.lastname: Tsukamoto
authors.forename: Shinobu
authors.initials: S
authors.lastname: Yasuo
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Masuda
authors.forename: Tadashi
authors.initials: T
authors.lastname: Yanagisawa
authors.forename: Shizufumi
authors.initials: S
authors.lastname: Ebihara
authors.forename: Takashi
authors.initials: T
authors.lastname: Yoshimura
mesh_terms: D000818:Animals; D001692:Biological Transport; D001717:Birds; D001921:Brain / Q000378:metabolism; D016466:CHO Cells; D002645:Chickens; D003001:Cloning, Molecular; D019295:Computational Biology; D003370:Coturnix; D006224:Cricetinae; D004247:DNA / Q000378:metabolism; D017931:DNA Primers / Q000737:chemistry; D030541:Databases, Genetic; D006066:Gonads / Q000378:metabolism; D007031:Hypothalamus / Q000378:metabolism; D017403:In Situ Hybridization; D007700:Kinetics; D008027:Light; D008297:Male; D008565:Membrane Proteins / Q000096:biosynthesis* / Q000502:physiology*; D008954:Models, Biological; D027361:Organic Anion Transporters / Q000096:biosynthesis* / Q000502:physiology*; D017440:Photoperiod; D010802:Phylogeny; D013963:Thyroid Hormones / Q000378:metabolism; D013974:Thyroxine / Q000378:metabolism; D013997:Time Factors
chemical_list: D017931:DNA Primers; D008565:Membrane Proteins; D027361:Organic Anion Transporters; C473187:SLCO1C1 protein, human; D013963:Thyroid Hormones; D004247:DNA; D013974:Thyroxine