Ziecik A J, Stanchev P D, Tilton J E
Endocrinology. 1986 Sep;119(3):1159-63. doi: 10.1210/endo-119-3-1159.
LH/hCG-binding sites were measured in crude membrane fractions of porcine uteri. Specific high affinity and low capacity receptors for LH/hCG were found in all (n = 17) membrane preparations of myometrium but in only 5 of 17 crude membrane fractions of endometrium of porcine uteri. There was very little competition between hCG and porcine GH (pGH), bovine TSH, pFSH, and pPRL (0.5%, 0.3%, 0.2%, and less than 0.005%, respectively). Specificity of [125I]hCG binding to other tissues was determined by incubating crude membrane preparations of heart, skeletal muscle, liver, and kidney. Numbers and affinities of available LH/hCG-binding sites were characterized in all samples of myometrium and 5 endometrium membrane preparations that were positive for LH/hCG receptors. The results indicate that the number of uterine LH-binding sites in myometrium (0.66 +/- 0.17 fmol/mg) is 10 times less than the receptor capacity in porcine corpora lutea (7.46 +/- 0.54 fmol/mg) when expressed per mg protein of crude membrane preparation. However, it is approximately 60 times less when expressed per mg DNA equivalent of initial homogenate (1.31 +/- 0.28 vs. 81.18 +/- 3.64 fmol/mg, respectively). Receptor affinities of uterine LH/hCG-binding sites remained comparable to those of corpora lutea receptors (Ka = 7.8 X 10(10) M-1). Concentrations of LH/hCG-binding sites in myometrium taken from gilts in the late follicular phase of the estrous cycle (0.13 +/- 0.06 fmol/mg protein; n = 5) were significantly less (P less than 0.05 and P less than 0.01) compared to those in myometrium from luteal phase (0.85 +/- 0.22 fmol/mg protein; n = 6) or early pregnancy (1.03 +/- 0.15 fmol/mg protein; n = 6), respectively. This is probably the first evidence demonstrating specific binding of [125I]hCG by LH receptors in female uterine tissue.
在猪子宫的粗膜组分中检测了促黄体生成素/人绒毛膜促性腺激素（LH/hCG）结合位点。在所有（n = 17）子宫肌层膜制剂中均发现了对LH/hCG具有特异性高亲和力和低容量的受体，但在猪子宫内膜的17个粗膜组分中仅5个发现了此类受体。hCG与猪生长激素（pGH）、牛促甲状腺激素（TSH）、猪促卵泡激素（pFSH）和猪催乳素（pPRL）之间的竞争非常小（分别为0.5%、0.3%、0.2%和小于0.005%）。通过孵育心脏、骨骼肌、肝脏和肾脏的粗膜制剂来确定[125I]hCG与其他组织结合的特异性。在所有子宫肌层样本以及5个对LH/hCG受体呈阳性的子宫内膜膜制剂中，对可用LH/hCG结合位点的数量和亲和力进行了表征。结果表明，以粗膜制剂每毫克蛋白质表示时，子宫肌层中子宫LH结合位点的数量（0.66±0.17 fmol/mg）比猪黄体中的受体容量（7.46±0.54 fmol/mg）少10倍。然而，以初始匀浆每毫克DNA当量表示时，其大约少60倍（分别为1.31±0.28与81.18±3.64 fmol/mg）。子宫LH/hCG结合位点的受体亲和力与黄体受体的亲和力相当（Ka = 7.8×10(10) M-1）。与发情周期黄体期（0.85±0.22 fmol/mg蛋白质；n = 6）或妊娠早期（1.03±0.15 fmol/mg蛋白质；n = 6）子宫肌层中的浓度相比，处于发情周期卵泡晚期的后备母猪子宫肌层中LH/hCG结合位点的浓度（0.13±0.06 fmol/mg蛋白质；n = 5）显著更低（P＜0.05和P＜0.01）。这可能是首次证明女性子宫组织中LH受体对[125I]hCG具有特异性结合的证据。
