title: LH release, induction of oestrus and fertile ovulations in response to pulsatile administration of GnRH to anoestrous dogs.
abstract: In one study in 33 bitches, in which each of seven doses of GnRH were injected into six anoestrous bitches each, doses of > or = 400 ng kg-1 released LH consistently, and doses of < or = 200 ng kg-1 did not. In a second study, GnRH was administered in pulses of 15-500 ng kg-1 every 90 min for 7-9 days to 36 anoestrous bitches, four prepubertal bitches and three luteal phase bitches. In 36 anoestrous bitches, GnRH pulses resulted in pro-oestrus, oestrus, ovulation and pregnancy in 26, 20, 16 and 12 bitches, respectively. Mean time for pro-oestrus onset, oestrus, ovulatory LH surge and parturition were 5.1 +/- 0.4, 11.2 +/- 0.7, 14.0 +/- 9.0, and 77.3 +/- 1.0 days, respectively, from start of treatment. In response to GnRH, pro-oestrus and pregnancy occurred in two of four prepubertal bitches, and pro-oestrus but not ovulation occurred in one of three luteal phase bitches. Efficacy in anoestrous bitches was dose dependent with high doses of > 280 ng kg-1 (n = 12) versus intermediate 85-270 ng kg-1 (n = 12) and low < 85 ng kg-1 doses (n = 12) resulting in a higher incidence of pro-oestrus (100 versus 80 and 33%), oestrus (92 versus 50 and 25%), ovulation (84 versus 42 and 8%) and pregnancy (58 versus 33 and 8%). With few exceptions, failed or weak responses were related to inadequate LH release, as measured in frequently collected samples following successive pulses on selected days of treatment; vaginal cornification, oestrous behaviour, and LH response were similar in oestrus without ovulation and fertile oestrus except for the lack of an ovulatory LH surge.
authors.affiliation: Dept of Physiology, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
authors.forename: P
authors.initials: P
authors.lastname: Concannon
authors.forename: B
authors.initials: B
authors.lastname: Lasley
authors.forename: S
authors.initials: S
authors.lastname: Vanderlip
mesh_terms: D000780:Anestrus / Q000187:drug effects*; D000818:Animals; D004285:Dogs / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D004971:Estrus / Q000187:drug effects*; D005260:Female; D005298:Fertility / Q000187:drug effects*; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology*; D008183:Luteal Phase / Q000187:drug effects; D007986:Luteinizing Hormone / Q000097:blood / Q000378:metabolism*; D010060:Ovulation / Q000187:drug effects*; D010062:Ovulation Induction / Q000379:methods / Q000662:veterinary; D011247:Pregnancy; D011374:Progesterone / Q000097:blood; D012741:Sexual Maturation / Q000187:drug effects
chemical_list: D007987:Gonadotropin-Releasing Hormone; D011374:Progesterone; D007986:Luteinizing Hormone