Nash S J, Brawer J, Robaire B, Ruf K B
Biol Reprod. 1986 Apr;34(3):549-57. doi: 10.1095/biolreprod34.3.549.
Our aim was to identify age-related changes in the dynamics of luteinizing hormone (LH) release that may contribute to the decline in pituitary sensitivity to luteinizing hormone-releasing hormone (LHRH) during sexual maturation of female rats. We studied LHRH-stimulated LH secretion curves of superfused pituitaries from rats ranging in age from 10 days to the first estrous cycle. Pituitary fragments were exposed for 10 min to medium alone or to medium plus LHRH; incubation continued in medium alone for 130 min and effluent was collected for LH analysis. Secretion curves were compared on the basis of total secretion (area under the curve), maximal change in LH secretion rate, and rates of rise and decay of the curves. The data show that total LH secretion in response to LHRH is greatest in 15-, 20-day-old and first-proestrus animals. Also, the maximal change in LH secretion rate was greater, and the increase in LH secretion rate faster in younger animals than in 30-day-old animals. Analysis of secretory granules in LH-containing gonadotropes of 15- and 30-day-old animals revealed changes in he granule population with age. We conclude that younger animals respond faster with a greater LH secretion response to LHRH than do 30-day-old or first-estrus animals, and that these age-related changes in the dynamics of LH secretion may be due in part to maturation of the LH secretory granules.
我们的目的是确定促黄体生成素（LH）释放动态中与年龄相关的变化，这些变化可能导致雌性大鼠性成熟期间垂体对促黄体生成素释放激素（LHRH）的敏感性下降。我们研究了年龄从10天到首次发情周期的大鼠的超灌流垂体对LHRH刺激的LH分泌曲线。将垂体碎片单独暴露于培养基中或暴露于添加LHRH的培养基中10分钟；然后在单独的培养基中继续孵育130分钟，并收集流出物用于LH分析。根据总分泌量（曲线下面积）、LH分泌率的最大变化以及曲线的上升和下降速率对分泌曲线进行比较。数据显示，15日龄、20日龄和首次发情前期动物对LHRH的总LH分泌量最大。此外，与30日龄动物相比，幼龄动物的LH分泌率最大变化更大，LH分泌率增加更快。对15日龄和30日龄动物含LH的促性腺激素细胞中的分泌颗粒分析显示，颗粒群体随年龄发生变化。我们得出结论，与30日龄或首次发情期动物相比，幼龄动物对LHRH的反应更快，LH分泌反应更大，并且LH分泌动态中这些与年龄相关的变化可能部分归因于LH分泌颗粒的成熟。
