title: Basal levels and GnRH-induced responses of peripheral testosterone and estrogen in Holstein bulls with poor semen quality.
abstract: The present study investigated the basal levels and GnRH-induced responses of peripheral testosterone and estrogen in Holstein bulls with poor semen quality. On the basis of semen parameters, bulls (n=5) having poor semen quality were selected as experimental bulls, and good semen quality bulls (n=4) were used as control bulls. Both groups were treated intramuscularly once with GnRH (250 µg of fertirelin acetate). Blood samples were collected at -1 day (d), -30 min and 0 h (treatment) followed by every 30 min for 5 h and 1, 3 and 5 d post-GnRH treatment (PGT), and LH, testosterone and estradiol-17β (E(2)) concentrations were measured. The pretreatment concentrations were used as basal levels. The percentage increments based on the 0-h levels were calculated per bull for each sampling time until 5 h PGT, and differences were compared between the experimental and control groups. The PGT concentrations of testosterone and basal and PGT concentrations of E(2) were significantly lower in the experimental group. The testosterone increment in the experimental group was delayed and significantly lower from 1 to 5 h PGT than those in the control group. It can be suggested that bulls with poor semen quality have delayed and lower GnRH-induced testosterone response and may also have lower estrogen levels.
authors.affiliation: Department of Veterinary Medicine, Obihiro University, Obihiro, Japan. bhumi@iwate-u.ac.jp
authors.forename: Bhuminand
authors.initials: B
authors.lastname: Devkota
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Takahashi
authors.forename: Shigenori
authors.initials: S
authors.lastname: Matsuzaki
authors.forename: Motozumi
authors.initials: M
authors.lastname: Matsui
authors.forename: Akio
authors.initials: A
authors.lastname: Miyamoto
authors.forename: Norio
authors.initials: N
authors.lastname: Yamagishi
authors.forename: Takeshi
authors.initials: T
authors.lastname: Osawa
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Hashizume
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Izaike
authors.forename: Yoh-Ichi
authors.initials: Y
authors.lastname: Miyake
mesh_terms: D000818:Animals; D002417:Cattle; D004967:Estrogens / Q000097:blood*; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology*; D008297:Male; D012661:Semen / Q000187:drug effects*; D055101:Semen Analysis; D013739:Testosterone / Q000097:blood*
chemical_list: D004967:Estrogens; D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone