Auger A P, Blaustein J D
Neuroscience and Behavior Program, University of Massachusetts, Amherst 01003.
J Neurosci. 1995 Mar;15(3 Pt 2):2272-9. doi: 10.1523/JNEUROSCI.15-03-02272.1995.
In female rats, the onset of reproductive behavior depends on the sequential presence of estradiol followed by progesterone. Although treatment with high doses of estradiol has been shown to increase immunostaining for the Fos protein, an immediate early gene product that is expressed upon cellular activation, another report conflicts with this finding. However, the previous reports agree that subsequent treatment with progesterone has no apparent effect on Fos expression. In order to resolve this discrepancy and investigate possible effects of progesterone, we used Fos immunocytochemistry combined with computer-aided image analysis. In experiment one, we found that treatment with 5 micrograms of estradiol increased Fos immunoreactivity (Fos-IR) within a section of the medial preoptic area and the dorsal medial hypothalamus. Subsequent treatment with 500 micrograms of progesterone 1 hr before perfusion increased the intensity of the immunostaining within the medial preoptic area and the dorsal medial hypothalamus, although it had no significant effect on Fos-IR cell number. In experiment 2, a lower concentration of Fos antiserum was used in order to diminish the immunostaining sensitivity to a level in which no increase of Fos-IR cell number was observed after treatment with estradiol. Under these immunocytochemical conditions, subsequent treatment with progesterone increased the number of Fos-IR cells in the medial preoptic area, the dorsal medial hypothalamus and the steroid receptor-rich area lateral to the ventromedial hypothalamus. Thus, treatment with behaviorally effective doses of both estradiol and progesterone induces Fos expression in localized regions of female rat brain.
在雌性大鼠中，生殖行为的开始取决于雌二醇随后是孕酮的相继存在。尽管已表明用高剂量雌二醇处理可增加Fos蛋白的免疫染色，Fos蛋白是一种在细胞活化时表达的立即早期基因产物，但另一篇报道与这一发现相矛盾。然而，先前的报道一致认为，随后用孕酮处理对Fos表达没有明显影响。为了解决这一差异并研究孕酮的可能作用，我们使用Fos免疫细胞化学结合计算机辅助图像分析。在实验一中，我们发现用5微克雌二醇处理可增加内侧视前区和下丘脑背内侧部分区域内的Fos免疫反应性（Fos-IR）。在灌注前1小时用500微克孕酮进行后续处理，增加了内侧视前区和下丘脑背内侧部分区域内的免疫染色强度，尽管对Fos-IR细胞数量没有显著影响。在实验2中，使用了较低浓度的Fos抗血清，以便将免疫染色敏感性降低到在用雌二醇处理后未观察到Fos-IR细胞数量增加的水平。在这些免疫细胞化学条件下，随后用孕酮处理增加了内侧视前区、下丘脑背内侧部分区域以及下丘脑腹内侧外侧富含类固醇受体区域内的Fos-IR细胞数量。因此，用行为有效剂量的雌二醇和孕酮处理均可诱导雌性大鼠脑局部区域的Fos表达。
