Ranke M B, Stanley C A, Tenore A, Rodbard D, Bongiovanni A M, Parks J S
Endocrinology. 1976 Oct;99(4):1033-45. doi: 10.1210/endo-99-4-1033.
Suspensions of rat hepatocytes isolated enzymatically by the method of Berry and Friend were used to study the binding of 125I-labeled human (hGH) and bovine (bGH) growth hormones and ovine prolactin (oPRL). Displacement of these labeled hormones by their unlabeled analogues was analyzed by means of Scatchard plots and affinity constants (K) and the number of binding sites per cell (q) were calculated. Specificity of binding was studied using hGH, bGH oPRL and rat growth hormone (rGH) and rat prolactin (rPRL). Rat hepatocytes contained two types of binding sites which bound hGH. The first, somatogenic, was specific for the growth-promoting hormones bGH and rGH. The second, lactogenic, was specific for lactogenic hormones, oPRL and rPRL. Human GH, which has both lactogenic and growth-promoting properties in rodents, bound to both sites. The somatogenic binding sites were present in both males and females, and the number of sites was similar in females and in males and was not affected by hypophysectomy. The lactogenic binding sites were present only in females, and the number of lactogenic and somatogenic sites was similar (40,000/cell). The affinity of hGH for the lactogenic binding sites was less than for the somatogenic (0.37 X 10(9) vs. 1 X 10(9)M-1). The lactogenic binding sites were lost when female rats were hypophysectomized and could not be restored by estrogen treatment.
采用Berry和Friend的方法酶法分离大鼠肝细胞悬液，用于研究125I标记的人（hGH）、牛（bGH）生长激素和羊催乳素（oPRL）的结合情况。通过Scatchard图分析这些标记激素被其未标记类似物取代的情况，并计算亲和常数（K）和每个细胞的结合位点数（q）。使用hGH、bGH、oPRL、大鼠生长激素（rGH）和大鼠催乳素（rPRL）研究结合的特异性。大鼠肝细胞含有两种结合hGH的位点。第一种是促生长的，对促生长激素bGH和rGH具有特异性。第二种是催乳的，对催乳激素oPRL和rPRL具有特异性。在啮齿动物中兼具催乳和促生长特性的人GH与这两种位点都结合。促生长结合位点在雄性和雌性中均存在，雌性和雄性中的位点数相似，且不受垂体切除的影响。催乳结合位点仅存在于雌性中，催乳和促生长位点的数量相似（40,000/细胞）。hGH对催乳结合位点的亲和力低于对促生长结合位点的亲和力（0.37×10^9对1×10^9M-1）。雌性大鼠垂体切除后，催乳结合位点消失，雌激素处理无法恢复。
