title: Age-related changes of reproductive hormones in young Meishan boars.
abstract: Meishan pigs are known for their early sexual maturity. On the other hand, they grow slowly. There is no information currently available about the combination of these two characteristics in Meishan pigs. To study the developmental characteristics of Meishan pigs, the plasma concentrations of LH, FSH, inhibin, testosterone, estradiol-17beta, progesterone and insulin-like growth factor-I (IGF-I) in young Meishan boars were determined using RIA and ELISA. Inhibin decreased with age in weeks, while testosterone and estradiol-17 beta increased. Testosterone increased gradually, and an increase in estradiol-17beta occurred after sexual maturity. IGF-I increased before puberty and subsequently decreased just after puberty like a pubertal IGF-1 surge. FSH, LH and progesterone did not change with age. There was no significant correlation among the hormones. During the experimental period, the Meishan boars showed large individual differences. These differences may depend on the fact that Meishan boar reach maturity at 12 weeks of age and continue to grow thereafter.
authors.affiliation: Endocrinology and Metabolism Research Team, National Institute of Livestock and Grassland Science, Tsukuba Norin Kenkyu Danchi, Tsukuba, Ibaraki, Japan. kaja@affrc.go.jp
authors.forename: Nobue
authors.initials: N
authors.lastname: Kanematsu
authors.forename: Wanzhu
authors.initials: W
authors.lastname: Jin
authors.forename: Gen
authors.initials: G
authors.lastname: Watanabe
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Taya
mesh_terms: D000367:Age Factors; D000818:Animals; D012739:Gonadal Steroid Hormones / Q000097:blood*; D006065:Gonadotropins, Pituitary / Q000097:blood*; D007265:Inhibins / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D013552:Swine / Q000097:blood* / Q000254:growth & development
chemical_list: D012739:Gonadal Steroid Hormones; D006065:Gonadotropins, Pituitary; D007265:Inhibins; D007334:Insulin-Like Growth Factor I