Shughrue P J, Stumpf W E, Elger W, Schulze P E, Sar M
Department of Cell Biology and Anatomy, University of North Carolina, Chapel Hill 27599.
Endocrinology. 1991 Jan;128(1):87-95. doi: 10.1210/endo-128-1-87.
The present study examined the number and distribution of progestin receptor cells in the 8-day-old male and female cortex and compared cortical labeling with that in the preoptic area and central hypothalamus. Eight-day postnatal mice (four males and four females), treated with estradiol, were each sc injected with 0.32 micrograms/100 g BW [125I]progestin (SA, 2200 Ci/mM). Brains were frozen 2 h after injection of [125I]progestin, sectioned, and processed for thaw-mount autoradiography. Cells with a nuclear concentration of radioactivity were localized in lamina VI of the lateral cortical regions of the male and female brain, while only a few cortical cells were seen in laminae II, III, and V of the suprarhinal, lateral, and cingulate/paracingulate regions. Comparison of the number of labeled cells revealed that the female cortex contained significantly more labeled cells than the male at three of the four levels investigated. Similarly, the number of target cells was higher in the female medial preoptic nucleus, but not in the arcuate nucleus and ventromedial hypothalamic nucleus, while the distributions of labeled cells in the male and female preoptic/hypothalamic regions were comparable. Injection of unlabeled progesterone or R5020 1 h before [125I]progestin reduced the nuclear concentration of radioactivity in all target regions and verified the specificity of [125I]progestin for the progestin receptor. The results of these studies indicate that mouse 8-day-old cortex and preoptic area in the female animal have more progestin receptor cells than those in the male and demonstrate that progestin receptor cells are localized in a region of the cortex known to contain few estrogen target cells. These results further suggest that a sexual dimorphism in progestin cell number may result in a differential effect of progestin on the cortex and preoptic area of the mouse, perhaps establishing a dimorphism in development and function.
本研究检测了8日龄雄性和雌性小鼠大脑皮质中孕激素受体细胞的数量和分布，并将皮质标记情况与视前区和下丘脑中部的进行了比较。对8日龄的小鼠（4只雄性和4只雌性）注射雌二醇后，每只小鼠皮下注射0.32微克/100克体重的[125I]孕激素（比活度，2200居里/毫摩尔）。注射[125I]孕激素2小时后将大脑冷冻，切片，并进行冻融放射自显影处理。放射性集中在细胞核的细胞定位于雄性和雌性大脑外侧皮质区域的VI层，而在鼻上、外侧和扣带/旁扣带区域的II、III和V层仅可见少数皮质细胞。标记细胞数量的比较显示，在所研究的四个水平中的三个水平上，雌性皮质中的标记细胞明显多于雄性。同样，雌性内侧视前核中的靶细胞数量较多，但在弓状核和腹内侧下丘脑核中并非如此，而雄性和雌性视前区/下丘脑区域中标记细胞的分布具有可比性。在注射[125I]孕激素前1小时注射未标记的孕酮或R5020可降低所有靶区域中放射性的核浓度，并证实了[125I]孕激素对孕激素受体的特异性。这些研究结果表明，雌性动物8日龄的小鼠大脑皮质和视前区中的孕激素受体细胞比雄性的更多，并证明孕激素受体细胞定位于皮质中已知含雌激素靶细胞较少的区域。这些结果进一步表明，孕激素细胞数量的性别二态性可能导致孕激素对小鼠大脑皮质和视前区产生不同的影响，这可能在发育和功能上形成一种二态性。
