Ziecik A J, Derecka-Reszka K, Rzucidło S J
Division of Reproductive Endocrinology and Pathophysiology, Polish Academy of Sciences, Olsztyn.
J Physiol Pharmacol. 1992 Dec;43(4 Suppl 1):33-49.
Luteinizing hormone (LH) and a second pituitary gonadotropin, follicle-stimulating hormone (FSH), together control steroid secretion and gamete development in both males and females. LH and its agonist human chorionic gonadotropin (hCG), share a common receptor in gonadal cells. There is increasing evidence for the existence of extraovarian LH/hCG binding sites in mammalian females. High affinity, low capacity LH/hCG receptors have been detected in pigs, rabbits and rats. Gonadotropin receptors in the human uterus were also demonstrated using immunocytochemical techniques. The presence of LH/hCG receptors, both in the endometrium and myometrium, has been so far found in pigs and humans. Receptors in the endometrium are present in glandular and luminal epithelium and stromal cells. In the myometrium, they are present in circular and longitudinal myometrial smooth muscle and vascular smooth muscle. Recently, LH/hCG receptor gene expression was confirmed both in the endometrium and myometrium of the pig. The amount of receptors is higher in the luteal phase as compared to the follicular phase of the estrous cycle indicating possible regulation of these receptors by ovarian hormones. Treatment with estradiol benzoate increased the number of LH/hCG binding sites compared with ovariectomized gilts receiving corn oil. However, administration of progesterone caused an elevation of these receptors, when compared with estradiol. Combined administration of estradiol and progesterone increased receptor capacity similar to progesterone alone. It seems that there are species differences in the uterine binding response to estradiol since the positive response to estradiol by uterine receptors in the ovariectomized pig is quite different from that observed in rabbits and rats. In the endometrium, hCG and/or LH may regulate glandular and luminal epithelial cell function via cAMP modulation or by increasing the local synthesis of steroid hormones. Stimulation of LH receptors with hCG in estrogen primed ovariectomized gilts had a quiescent effect on myometrial contractility in vitro. We examined also the effect of hCG on electromyographic activities of the uterus in ovariectomized and estrogen treated pigs. The hCG treatment caused a significant reduction of total duration of electrical activity and mean burst duration. Based on our earlier and recent results we suggest that the role of LH/hCG receptors in the myometrium is the regulation of uterine contractility, though the second messenger system remains to be elucidated.
促黄体生成素（LH）和另一种垂体促性腺激素——促卵泡激素（FSH）共同控制着雄性和雌性的类固醇分泌及配子发育。LH及其激动剂人绒毛膜促性腺激素（hCG）在性腺细胞中共享一种共同受体。越来越多的证据表明，在哺乳动物雌性体内存在卵巢外LH/hCG结合位点。在猪、兔和大鼠中已检测到高亲和力、低容量的LH/hCG受体。利用免疫细胞化学技术也证实了人子宫中存在促性腺激素受体。迄今为止，在猪和人体内都发现子宫内膜和子宫肌层中存在LH/hCG受体。子宫内膜中的受体存在于腺上皮、腔上皮和基质细胞中。在子宫肌层中，它们存在于环形和纵形子宫肌层平滑肌以及血管平滑肌中。最近，在猪的子宫内膜和子宫肌层中都证实了LH/hCG受体基因的表达。与发情周期的卵泡期相比，黄体期的受体数量更高，这表明这些受体可能受卵巢激素调节。与接受玉米油的去卵巢后备母猪相比，苯甲酸雌二醇处理增加了LH/hCG结合位点的数量。然而，与雌二醇相比，孕酮的给药导致这些受体数量增加。雌二醇和孕酮联合给药增加的受体容量与单独使用孕酮相似。由于去卵巢猪子宫受体对雌二醇的阳性反应与在兔和大鼠中观察到的反应有很大不同，似乎子宫对雌二醇的结合反应存在物种差异。在子宫内膜中，hCG和/或LH可能通过cAMP调节或增加类固醇激素的局部合成来调节腺上皮和腔上皮细胞功能。在雌激素预处理的去卵巢后备母猪中，用hCG刺激LH受体对子宫肌层收缩性在体外有静止作用。我们还研究了hCG对去卵巢并经雌激素处理的猪子宫肌电图活动的影响。hCG处理导致电活动总持续时间和平均爆发持续时间显著缩短。基于我们早期和近期的研究结果，我们认为LH/hCG受体在子宫肌层中的作用是调节子宫收缩性，尽管第二信使系统仍有待阐明。
