Detection of LH release from individual pituitary cells by the reverse hemolytic plaque assay: estrogen increases the fraction of gonadotropes responding to GnRH.
Detection of LH release from individual pituitary cells by the reverse hemolytic plaque assay: estrogen increases the fraction of gonadotropes responding to GnRH.
复制标题
通过反向溶血斑测定检测单个垂体细胞释放的 LH：雌激素增加对 GnRH 做出反应的促性腺激素的比例。
作者：
P. F. Smith;L. Frawley;J. D. Neill
促性腺激素分泌LH在显微镜下显示混合垂体前叶（AP）细胞培养与反向溶血斑块试验。从细胞中释放的黄体生成素与携带黄体生成素ab蛋白a复合物的邻近红细胞结合，在每个促性腺激素周围形成补体介导的溶血区（斑块）。在未经处理的培养中，形成了一些小斑块，但在下丘脑GnRH （10(-7) M，最大刺激剂量）的存在下，斑块的数量和大小增加了10倍。在发情动物的垂体中发现了非分泌性促性腺激素：所有AP细胞中有5-6%含有免疫细胞化学检测到的LH，而只有2.5-3.0%在GnRH存在下形成斑块（10(-7)M）。几乎所有促性腺激素都在发情期分泌。雌二醇对发情培养物处理24 h后，促性腺激素的分泌率提高到接近发情培养物的水平。这些结果证明了反向溶血斑块法检测单个促性腺激素促黄体生成素分泌的效用，证实了并非所有含有促黄体生成素的细胞都能分泌促黄体生成素，并表明一种以前未被认识到的雌激素作用模式通过增加促性腺激素分泌的比例来介导促黄体生成素的促排卵激增。
Gonadotropes that secrete LH were demonstrated microscopically among mixed anterior pituitary (AP) cells in culture with a reverse hemolytic plaque assay. LH released from a cell binds to adjacent RBCs bearing an LH Ab-protein A complex which results in a zone of complement-mediated hemolysis (a plaque) surrounding each gonadotrope. In untreated cultures a few, small plaques formed, but in the presence of hypothalamic GnRH (10(-7) M, a maximally stimulating dose) a 10-fold increase occurred in their number and size. Non-secretory gonadotropes were found in the pituitary of diestrous animals: 5-6% of all AP cells contained immunocytochemically detectable LH whereas only 2.5-3.0% formed plaques in the presence of GnRH (10(-7) M). Nearly all of the gonadotropes were secretory at proestrus. Estradiol treatment of diestrous cultures for 24 h increased the fraction of secretory gonadotropes to near the level observed in proestrous cultures. These results demonstrate the utility of the reverse hemolytic plaque assay for detection of LH secretion from individual gonadotropes, establish that not all cells containing LH can secrete it, and suggest that a previously unrecognized mode of estrogen action to evoke the preovulatory LH surge is mediated by increasing the fraction of secretory gonadotropes.