Garcia-Segura L M, Luquín S, Párducz A, Naftolin F
Instituto Cajal, C.S.I.C., Madrid, Spain.
Glia. 1994 Jan;10(1):59-69. doi: 10.1002/glia.440100108.
The influence of gonadal steroids on the ultrastructure of glial cells and on the immunoreactivity for the specific astrocytic marker glial fibrillary acidic protein (GFAP) has been assessed in the neuroendocrine hypothalamus. The following parameters were analyzed in the arcuate nucleus of adult female rats: the number and the surface density of cells immunoreactive for GFAP, the number of glial profiles showing bundles of glial filaments, the size of the bundles of glial filaments, and the proportion of neuronal perikaryal membrane apposed by glial processes. These parameters were studied during the different phases of the estrous cycle, after ovariectomy, and after the administration of estradiol or progesterone to ovariectomized rats. No significant differences were detected in the number of GFAP-immunoreactive cells among the different experimental groups. The surface density of GFAP-immunoreactive material, the number of glial profiles in the neuropil, and the proportion of neuronal perikaryal membrane covered by glia were increased in the afternoon of proestrus and in the morning of estrus compared with other phases of the estrous cycle or to ovariectomized rats and showed a rapid (5 h) and reversible increase in ovariectomized rats injected with 17 beta estradiol, with a maximal effect by 24 h after the administration of the hormone. In contrast, the size of the bundles of glial filaments was decreased in the afternoon of proestrus, in the morning of estrus, and by the administration of estradiol to ovariectomized rats. The parameters studied were not affected by the administration of progesterone. However, progesterone (300 micrograms/rat) blocked the effects of 17 beta estradiol (1, 10, and 300 micrograms). The results suggest that glial cells may be actively involved in the modulation of neuroendocrine events by the hypothalamus.
性腺类固醇对神经内分泌下丘脑神经胶质细胞超微结构以及对特异性星形胶质细胞标志物胶质纤维酸性蛋白（GFAP）免疫反应性的影响已得到评估。对成年雌性大鼠弓状核分析了以下参数：GFAP免疫反应性细胞的数量和表面密度、显示胶质丝束的胶质细胞轮廓数量、胶质丝束的大小以及被胶质细胞突起包围的神经元胞核周膜的比例。在发情周期的不同阶段、卵巢切除术后以及对卵巢切除的大鼠给予雌二醇或孕酮后，对这些参数进行了研究。在不同实验组之间，未检测到GFAP免疫反应性细胞数量有显著差异。与发情周期的其他阶段或卵巢切除的大鼠相比，在动情前期下午和发情期上午，GFAP免疫反应性物质的表面密度、神经毡中胶质细胞轮廓的数量以及被胶质细胞覆盖的神经元胞核周膜的比例均增加，并且在注射17β-雌二醇的卵巢切除大鼠中显示出快速（5小时）且可逆的增加，在激素给药后24小时达到最大效应。相反，在动情前期下午、发情期上午以及对卵巢切除大鼠给予雌二醇后，胶质丝束的大小减小。所研究的参数不受孕酮给药的影响。然而，孕酮（300微克/只大鼠）可阻断17β-雌二醇（1、10和300微克）的作用。结果表明，神经胶质细胞可能积极参与下丘脑对神经内分泌事件的调节。
