title: Seasonal expression of LHbeta and FSHbeta in the male newt pituitary gonadotrophs.
abstract: Seasonal changes in LHbeta and FSHbeta mRNA levels were examined in the pituitary gland of the adult male newt, Cynops pyrrhogaster, using in situ hybridization histochemistry and a quantitative real-time RT-PCR method. The annual fluctuation of LHbeta mRNA and FSHbeta mRNA levels in the pituitary gland displayed a close relationship with seasonal changes in testicular function. The values obtained by both methods showed similar fluctuation. The levels of LHbeta mRNA were always exceeded those of FSHbeta. The present immunoelectron microscopic observations support the data on the gene expression levels of the beta-subunits of LH and FSH. Gonadectomy in the summer increased the LHbeta and FSHbeta mRNA levels. Testosterone replacement inhibited the expression of LHbeta mRNA, but not of FSHbeta mRNA, suggesting that the expression of FSHbeta is regulated by some non-steroid factor, probably inhibin. In the case of gonadectomy during any other season, the LHbeta mRNA level increased, but not to the same extent as in summer, and androgen concentrations decreased to the minimum of the year. This finding provides new information about the regulation of annual changes in LHbeta and FSHbeta expression in the pituitary gonadotrophs.
authors.affiliation: Department of Biology, Faculty of Science, Shizuoka University, Shizuoka 422-8529, Japan.
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Kano
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Nakano
authors.forename: Masahiko
authors.initials: M
authors.lastname: Kumakura
authors.forename: Takashi
authors.initials: T
authors.lastname: Wasa
authors.forename: Masakazu
authors.initials: M
authors.lastname: Suzuki
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Yamauchi
authors.forename: Shigeyasu
authors.initials: S
authors.lastname: Tanaka
mesh_terms: D000818:Animals; D018870:Endoplasmic Reticulum, Rough / Q000648:ultrastructure; D037201:Follicle Stimulating Hormone, beta Subunit / Q000235:genetics*; D006056:Golgi Apparatus / Q000648:ultrastructure; D017403:In Situ Hybridization; D037101:Luteinizing Hormone, beta Subunit / Q000235:genetics*; D008297:Male; D016253:Microscopy, Immunoelectron; D010902:Pituitary Gland / Q000502:physiology* / Q000648:ultrastructure; D012333:RNA, Messenger / Q000032:analysis; D012098:Reproduction / Q000502:physiology; D012455:Salamandridae / Q000502:physiology*; D012621:Seasons
chemical_list: D037201:Follicle Stimulating Hormone, beta Subunit; D037101:Luteinizing Hormone, beta Subunit; D012333:RNA, Messenger