Crighton D B, Foster J P
J Endocrinol. 1977 Jan;72(1):59-67. doi: 10.1677/joe.0.0720059.
Anoestrous ewes were given two injections of 30 mug synthetic luteinizing hormone releasing hormone (LH-RH) separated by one of the following intervals: 1-5, 3, 6, 12 or 24 h. The first injection caused an increase in the plasma LH concentration in each animal. The response to the second injection was dependent on the interval between the injections. When the second injection was administered 1-5 h after the first it caused a further increase in the LH concentration to maximal levels which were significantly greater than those induced in the other anoestrous groups. When the second injection was administered 3 h after the first, there was no significant difference between the responses to the two injections although the time to reach the maximal LH concentration was shorter and the height of the LH peak was greater in each animal following the second injection. When the second injection was administered 6, 12 or 24 h after the first, the LH response was significantly less, in terms of height and area of the induced peak, than following the first injection. The LH response to the second injection was particularly low in the 12 and 24 h groups. Two injections of 30 mug synthetic LH-RH were also administered at 1-5 h intervals to ewes on either day 10 of the oestrous cycle or at onset of oestrus. The pattern of LH responses in all these animals was similar to that observed in anoestrous ewes injected at 1-5 h intervals. The total LH release, as assessed in terms of the induced peaks, was significantly greater in the onset of oestrus group than in the day 10 group or any of the anoestrous groups. Presumably the sensitization-desensitization sequence of the pituitary gland to LH-RH which has been demonstrated, together with the effects of sex steroid hormones, must play an important part in the development and decay of the natural preovulatory LH peak.
对处于乏情期的母羊注射两次30微克的合成促黄体生成激素释放激素（LH-RH），两次注射之间间隔以下时长之一：1 - 5小时、3小时、6小时、12小时或24小时。首次注射使每只动物的血浆LH浓度升高。对第二次注射的反应取决于两次注射之间的间隔。当第二次注射在首次注射后1 - 5小时进行时，它会使LH浓度进一步升高至最大水平，该水平显著高于其他乏情期组所诱导的水平。当第二次注射在首次注射后3小时进行时，两次注射的反应之间没有显著差异，尽管在第二次注射后，每只动物达到最大LH浓度的时间更短，且LH峰值更高。当第二次注射在首次注射后6小时、12小时或24小时进行时，就诱导峰值的高度和面积而言，LH反应明显低于首次注射后的反应。在12小时和24小时组中，对第二次注射的LH反应尤其低。在发情周期第10天或发情开始时，也以1 - 5小时的间隔对母羊注射两次30微克的合成LH-RH。所有这些动物的LH反应模式与以1 - 5小时间隔注射的乏情期母羊所观察到的模式相似。就诱导峰值评估，发情开始组的总LH释放量显著高于第10天组或任何乏情期组。据推测，已被证明的垂体对LH-RH的致敏 - 脱敏序列，连同性类固醇激素的作用，必定在自然排卵前LH峰值的形成和消退中起重要作用。
