McLeod B J, Haresign W, Lamming G E
J Reprod Fertil. 1982 May;65(1):223-30. doi: 10.1530/jrf.0.0650223.
Four groups, each of 5 seasonally anoestrous ewes, were treated i.v with small doses (75, 125, 250 or 500 ng) of Gn-RH at 2-h intervals for 48 h. A further 15 ewes received 14 days pretreatment with progesterone and then the 250 ng Gn-RH treatment. Gn-RH injections induced an episodic pattern of LH secretion which differed significantly for the doses of Gn-RH used. A preovulatory LH surge occurred in all but 1 of the ewes during the period of Gn-RH treatment. Ovulation occurred in all 15 ewes pretreated with progesterone and in 19/20 ewes treated with Gn-RH alone. Although normal luteal function occurred in all ewes pretreated with progesterone, it was present in only 5 of the 20 ewes treated with Gn-RH alone. Oestrus, as shown by mating, occurred at a mean time of 34.7 +/- 2.6 h after the start of Gn-RH treatment only in those ewes receiving progesterone pretreatment. These results indicate that progesterone pretreatment has a marked effect on the ability of small doses of Gn-RH to induce ovulation and normal luteal function in seasonally anoestrous ewes.
将四组，每组5只季节性乏情母羊，每隔2小时静脉注射小剂量（75、125、250或500纳克）的促性腺激素释放激素（Gn-RH），持续48小时。另外15只母羊先用孕酮预处理14天，然后进行250纳克Gn-RH的处理。Gn-RH注射诱导了促黄体生成素（LH）分泌的间歇性模式，所用Gn-RH剂量不同，该模式有显著差异。在Gn-RH治疗期间，除1只母羊外，所有母羊均出现了排卵前LH峰。用孕酮预处理的所有15只母羊以及仅用Gn-RH处理的20只母羊中的19只发生了排卵。虽然用孕酮预处理的所有母羊都出现了正常的黄体功能，但仅用Gn-RH处理的20只母羊中只有5只出现了黄体功能。只有那些接受孕酮预处理的母羊，在Gn-RH治疗开始后平均34.7±2.6小时出现了如交配所示的发情。这些结果表明，孕酮预处理对小剂量Gn-RH诱导季节性乏情母羊排卵和正常黄体功能的能力有显著影响。
