Central mechanism controlling the expression of estrous behavior and its manipulation in the dog.

研究了一种促性腺激素释放激素激动剂（GnRH-A）缓释制剂对犬生殖功能的刺激作用及控制发情行为表达的中枢机制。黄体生成素（LH）的平均血浆水平在停经中后期随着脉搏型的改变而升高，其次是雌激素和黄体酮的平均血浆水平升高。下丘脑GnRH释放的增加可能是黄体生成素分泌增加的原因，黄体生成素分泌增加是在发情过程中发生的。下丘脑雌激素受体基因表达增强，受雌激素调控，可能是导致GnRH释放增加的因素之一。在退情过程中，垂体GnRH受体基因表达增加，垂体相应应答。在发情的母狗中，雌激素通过增加其自身受体的浓度来增加子宫的敏感性，提示为发情做准备。单次注射GnRH-A缓释制剂可致发情母狗受热。上述结果提示，下丘脑雌激素受体基因在退情后期表达的增强，可能是控制发情行为表达的中枢机制，可能导致GnRH释放增加，而垂体对GnRH的反应性增加，导致卵巢和子宫活动随着发情的恢复而恢复。他们还表明，微胶囊化的LA可用于控制狗的生殖功能。

Central mechanism controlling the expression of estrous behavior and stimulatory effects of a sustained release formulation of the gonadotrophin-releasing hormone agonist (GnRH-A) on reproductive function in the dog were examined, and the following results were obtained.1. An increase in the mean plasma levels of luteinizing hormone (LH) occurred from mid to late anestrus with the change in pulse patterns, followed by an increase in the mean plasma levels of estrogen and progesterone.2. The increase in GnRH release from hypothalamus could be responsible for the increasing secretion of LH which occurs during the progression of anestrus.3. Enhancement of hypothalamic estrogen receptor gene expression which may be regulated by estrogen might be one factor leading to the increased GnRH release in late anestrus.4. During the course of anestrus pituitary GnRH receptor gene expression increased while the pituitary responded accordingly.5. In proestrous bitches estrogen increased uterine sensitivity by increasing it's own receptor concentration, suggesting the preparation for estrus.6. A single injection of sustained-release formulation of GnRH-A in anestrous bitches resulted in an induced heat.These results suggest that, as a possible central mechanism controlling the expression of estrous behavior, the enhancement of hypothalamic estrogen receptor gene expression in late anestrus may lead to the increase in GnRH release, while pituitary responsiveness to thereby resulting in the resumption of ovarian and uterine activity with the return to estrus. They also indicate that microencapsulated LA can be useful in controlling the reproductive function in the dog.