Sawitzke A L, Odell W D
Department of Physiology, University of Utah School of Medicine, Salt Lake City.
Acta Endocrinol (Copenh). 1991 Mar;124(3):322-30. doi: 10.1530/acta.0.1240322.
High-affinity LH/hCG binding sites have been identified in both porcine and rabbit uteri. We have now identified these binding sites in rat uteri. We have assessed the binding site specificity and modulation and have searched for binding sites for a related glycoprotein. Radioreceptor assays were performed with membrane homogenates of uterine tissue, and were analysed for binding site specificity, affinity, and capacity. The rabbit and rat LH/hCG binding sites did not bind human TSH or human FSH. Rabbit uterine tissue contained no binding sites for FSH, as determined with 125I-labelled FSH and unlabelled FSH. Pretreatment of rabbits with hCG decreased their uterine binding site capacity from 1.30 +/- 0.29 to 0.46 +/- 0.01 fmol/mg protein. Pretreatment of castrated rabbits with estrogen or estrogen combined with progesterone did not alter the binding site affinity or capacity. In rats, the uterine binding site number was shown to vary inversely with the serum LH concentration and directly with the ovarian LH/hCG binding site number during the estrus cycle. Hypophysectomy resulted in a significant increase in uterine binding site capacity in rats. Estrogen treatment prevented this hypophysectomy-induced increase. The function of these LH/hCG binding sites remains uncertain; however, the lack of binding sites for a related glycoprotein and the modulation of these binding sites by hormonal factors strengthen the concept that uterine tissue might respond in a specific manner to direct LH/hCG stimulation.
在猪和兔的子宫中均已鉴定出高亲和力的促黄体生成素/人绒毛膜促性腺激素（LH/hCG）结合位点。我们现已在大鼠子宫中鉴定出这些结合位点。我们评估了结合位点的特异性和调节作用，并寻找了一种相关糖蛋白的结合位点。采用子宫组织膜匀浆进行放射受体分析，并对结合位点的特异性、亲和力和容量进行分析。兔和大鼠的LH/hCG结合位点不与人促甲状腺激素（TSH）或人促卵泡激素（FSH）结合。用125I标记的FSH和未标记的FSH测定，兔子宫组织中不存在FSH结合位点。用hCG预处理兔后，其子宫结合位点容量从1.30±0.29飞摩尔/毫克蛋白降至0.46±0.01飞摩尔/毫克蛋白。用雌激素或雌激素与孕酮联合预处理去势兔，不会改变结合位点的亲和力或容量。在大鼠发情周期中，子宫结合位点数量与血清LH浓度呈负相关，与卵巢LH/hCG结合位点数量呈正相关。垂体切除导致大鼠子宫结合位点容量显著增加。雌激素处理可防止垂体切除引起的这种增加。这些LH/hCG结合位点的功能尚不确定；然而，缺乏相关糖蛋白的结合位点以及激素因素对这些结合位点的调节作用，强化了子宫组织可能以特定方式对直接的LH/hCG刺激作出反应的概念。
