Lado-Abeal J, Norman R L
Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock 79430, USA.
Neuroendocrinology. 1998 Apr;67(4):236-43. doi: 10.1159/000054319.
During puberty, primates begin to secrete LH, and presumably GnRH, at night and then eventually throughout the day as they mature. We examined the role of vasopressin, a putative inhibitor of the GnRH pulse generator, on LH secretion in pubertal male macaques both during the day when the GnRH pulse generator was not active and during the night when pulsatile LH secretion was observed. As has been found in other primates, LH and testosterone levels were low during the day and elevated at night. A potent vasopressin receptor antagonist (VPa) was administered during the middle 5 h of a 15-hour daytime or nighttime blood collection period to determine the effects on LH, testosterone and cortisol secretion. Both during the day and night, cortisol secretion was elevated during VPa infusion, suggesting that this V1a receptor antagonist has agonist activity on the V1b receptor in the pituitary involved in vasopressin-stimulated corticotropin release. Mean LH levels during VPa infusion were not different from the control period for that group during the day when LH secretion was absent. Mean LH levels were significantly higher (p < 0.05) than pre-VPa LH levels at night when pulsatile LH secretion was observed. However, LH levels at night during VPa were not higher than levels in untreated animals at the same time. The results of these studies demonstrate that LH and testosterone profiles are similar to those observed in human males during the pubertal transition and suggest that the absence of daytime gonadotropin release during puberty is not due to inhibitory vasopressinergic tone on the GnRH pulse generator.
在青春期，灵长类动物开始在夜间分泌促黄体生成素（LH），推测也分泌促性腺激素释放激素（GnRH），随着它们的成熟，最终会在全天分泌。我们研究了加压素（一种假定的GnRH脉冲发生器抑制剂）对青春期雄性猕猴LH分泌的作用，分别在GnRH脉冲发生器不活跃的白天以及观察到LH呈脉冲式分泌的夜间进行研究。正如在其他灵长类动物中所发现的那样，LH和睾酮水平在白天较低，在夜间升高。在15小时的白天或夜间采血期的中间5小时内给予一种强效的加压素受体拮抗剂（VPa），以确定其对LH、睾酮和皮质醇分泌的影响。无论是在白天还是夜间，在输注VPa期间皮质醇分泌均升高，这表明这种V1a受体拮抗剂对垂体中参与加压素刺激促肾上腺皮质激素释放的V1b受体具有激动剂活性。在白天LH分泌不存在时，输注VPa期间的平均LH水平与该组的对照期没有差异。在观察到LH呈脉冲式分泌的夜间，平均LH水平显著高于VPa给药前的LH水平（p < 0.05）。然而，VPa给药期间夜间的LH水平并不高于同时期未治疗动物的水平。这些研究结果表明，LH和睾酮的变化模式与青春期过渡期间人类男性中观察到的相似，并表明青春期白天促性腺激素释放的缺乏并非由于对GnRH脉冲发生器的抑制性加压素能张力所致。
