GROWTH-HORMONE (GH) RECEPTORS IN CLONAL OSTEOBLAST-LIKE CELLS MEDIATE A MITOGENIC RESPONSE TO GH
GROWTH-HORMONE (GH) RECEPTORS IN CLONAL OSTEOBLAST-LIKE CELLS MEDIATE A MITOGENIC RESPONSE TO GH
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DOI：
10.1210/endo-128-3-1459
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发表时间：
1991-03-01
期刊：
影响因子：
4.8
通讯作者：
WATERS, MJ
中科院分区：
文献类型：
--
作者：
BARNARD, R;NG, KW;WATERS, MJ
GH受体迄今尚未被证明或表征成骨细胞。 在这项研究中，我们报告的功能GH受体的克隆大鼠成骨细胞样细胞系UMR 106.06的特性。 该受体具有典型的体细胞特异性，对人GH具有高亲和力，对大鼠GH的亲和力低10倍，对大鼠PRL的亲和力非常差。 对大鼠GH的亲和力为1.2 +/- 0.4 x 10（9）M-1，每个细胞约有9000个受体。 生长激素结合增加了几个小时，当孵育进行无血清的基本必需培养基，但结合迅速减少，当孵育进行的Tris-NaCl-Mg++，HEPES，或碳酸氢盐缓冲液，这表明一个关键的依赖性受体表达的营养因素。 大鼠GH以剂量依赖性方式刺激UMR 106.06细胞增殖，最大刺激高于对照43 +/- 2%，在最终激素浓度为15 +/- 3 ng/ml时达到半数最大效应。 在低细胞密度下未观察到增殖反应，提示需要自分泌介质或密度依赖性受体表达的阈值浓度。 单克隆抗体（单克隆抗体263），它阻止GH结合到一个子集（1型）的大鼠肝GH受体没有阻止结合成骨细胞GH受体，并没有阻止增殖反应。 因此，增殖反应似乎是由一类GH受体介导的，不被MAb 263阻断，可能与2型肝GH受体相关。 从UMR 106.06细胞和第二成骨细胞样细胞系UMR 201中提取RNA。 用P-32标记的兔肝生长激素受体的互补DNA探针与两种细胞杂交，显示两条主要标记带（3.5和1.2个酶）和一条次要标记带（2.4个酶）。 UMR 106.06细胞为研究GH的作用机制提供了一个有价值的模型系统。
GH receptors have not hitherto been demonstrated or characterized on osteoblasts. In this study we report the characterization of functional GH receptors on the clonal rat osteoblast-like cell line UMR 106.06. The receptors have a typical somatogenic specificity, with high affinity for human GH, 10-fold lower affinity for rat GH, and very poor affinity for rat PRL. The affinity for rat GH is 1.2 +/- 0.4 x 10(9) M-1, and there are approximately 9000 receptors per cell. GH binding increased over several hours when incubations were carried out in serum free minimal essential medium, but binding reduced rapidly when incubations were carried out in Tris-NaCl-Mg++, HEPES, or bicarbonate buffer, suggesting a critical dependence of receptor expression on nutritional factors. Rat GH stimulated proliferation of UMR 106.06 cells in a dose-dependent fashion with a maximum 43 +/- 2% stimulation above control and half-maximal effect at a final hormone concentration of 15 +/- 3 ng/ml. A proliferative response was not observed at low cell density, suggestive of a requirement for a threshold concentration of autocrine mediators or density-dependent receptor expression. A monoclonal antibody (MAb 263) which blocks GH binding to a subset (type 1) of rat hepatic GH receptors did not block binding to osteoblast GH receptors, and did not block the proliferative response. Thus, the proliferative response appears to be mediated by a class of GH receptors not blocked by MAb 263 and possibly related to the type 2 hepatic GH receptors. RNA was extracted from UMR 106.06 cells and a second osteoblast-like cell line UMR 201. Hybridization to a P-32-labeled complementary DNA probe to the rabbit hepatic growth hormone receptor revealed two major labelled bands (3.5 and 1.2 kilobases) and one minor band (2.4 kilobases) in both cell types.In summary, GH receptors are present in clonal osteoblast-like cells, and the receptors mediate a proliferative response to GH. The UMR 106.06 cells provide a valuable model system for studying the mechanism of GH action.