title: Effect of immunization against GnRH on hypothalamic and testicular function in rams.
abstract: The objective was to determine effects of active immunization against GnRH on reproductive function in Tibetan rams. Peripubertal Tibetan rams (n = 30) were randomly and equally allocated into three groups: control (no treatment); surgically castrated; or immunized against 100-μg d-Lys6-GnRH-tandem-dimer peptide conjugated to ovalbumin in Specol adjuvant at 24 weeks of age (with a booster 8 weeks later). Blood samples (for antibody titers and hormone concentrations) were collected at 4-week intervals until rams were killed (40 weeks). Immunization triggered a good antibody response in all immunized rams (P < 0.01). Compared with intact controls, anti-GnRH immunization reduced (P < 0.01) serum concentrations of testosterone, inhibin A, LH, and FSH, and it induced testicular atrophy (suppression of spermatogenesis). Androstenone concentrations in fat tissues of GnRH-immunized rams were also rendered nondetectable (P < 0.001). Furthermore, mRNA expressions of GnRH receptor, LH-β, and FSH-β in the pituitary and of LH receptor, FSH receptor, and inhibin α and βA subunits in the testes were decreased in immunized rams compared with intact controls (P < 0.05). This was apparently the first report that active immunization against GnRH-tandem-dimer-ovalbumin conjugate in Specol adjuvant was an effective alternative to surgical castration for Tibetan rams under practical Tibetan plateau conditions.
authors.affiliation: Isotope Research Lab, Sichuan Agricultural University, Ya'an, P.R. China.
authors.forename: Xingfa
authors.initials: X
authors.lastname: Han
authors.affiliation: Isotope Research Lab, Sichuan Agricultural University, Ya'an, P.R. China.
authors.forename: Longjun
authors.initials: L
authors.lastname: Gu
authors.affiliation: Institute of Animal Science, Tibet Academy of Agricultural and Animal Husbandry Science, Lhasa, P.R. China.
authors.forename: Chenyang
authors.initials: C
authors.lastname: Xia
authors.affiliation: Institute of Animal Science, Tibet Academy of Agricultural and Animal Husbandry Science, Lhasa, P.R. China.
authors.forename: Jing
authors.initials: J
authors.lastname: Feng
authors.affiliation: Isotope Research Lab, Sichuan Agricultural University, Ya'an, P.R. China.
authors.forename: Xiaohan
authors.initials: X
authors.lastname: Cao
authors.affiliation: Isotope Research Lab, Sichuan Agricultural University, Ya'an, P.R. China.
authors.forename: Xiaogang
authors.initials: X
authors.lastname: Du
authors.affiliation: Isotope Research Lab, Sichuan Agricultural University, Ya'an, P.R. China. Electronic address: xyzeng1966@163.com.
authors.forename: Xianyin
authors.initials: X
authors.lastname: Zeng
authors.affiliation: Institute of Animal Science, Tibet Academy of Agricultural and Animal Husbandry Science, Lhasa, P.R. China. Electronic address: songtianzeng@china.com.cn.
authors.forename: Tianzeng
authors.initials: T
authors.lastname: Song
mesh_terms: D000818:Animals; D007987:Gonadotropin-Releasing Hormone / Q000276:immunology*; D007031:Hypothalamus / Q000276:immunology / Q000502:physiology*; D008297:Male; D009919:Orchiectomy / Q000379:methods / Q000662:veterinary*; D012756:Sheep; D013737:Testis / Q000276:immunology* / Q000502:physiology; D022642:Vaccines, Contraceptive / Q000276:immunology*
chemical_list: D022642:Vaccines, Contraceptive; D007987:Gonadotropin-Releasing Hormone
keywords: GnRH; Immunization; Ram; Reproductive function; Tibetan