Podestá E J, Solano A R, Sánchez M L
Endocrinology. 1986 Sep;119(3):989-97. doi: 10.1210/endo-119-3-989.
LH receptor internalization was studied with an antireceptor monoclonal antibody (aLHR) which induces Leydig cells to produce testosterone. To follow receptor-mediated aLHR internalization, cells were incubated with aLHR at 10 C for 3 h to generate an aLHR complex; this was followed by a second incubation with fluorescent labeled antimouse immunoglobulin at 34 C, a temperature which allows internalization. Within 15 min at 34 C, cytoplasmic fluorescent staining was detectable; this staining was strongly visible after 60 min. At no time was nuclear staining observable. Employing such an approach, it has also been possible to follow the fate of unoccupied receptors when cells are stimulated with a submaximal dose of LH. The results show that LH interactions with 20% of its receptors produces microaggregation, patching, capping, and internalization of free receptor sites. The results further demonstrate that cells with receptors in the state of capping are less sensitive to a second LH stimulation, suggesting that in this state receptors are no longer coupled to the adenylate cyclase system.
利用一种抗受体单克隆抗体（aLHR）研究促黄体生成素（LH）受体的内化，该抗体可诱导睾丸间质细胞产生睾酮。为追踪受体介导的aLHR内化过程，将细胞与aLHR在10℃孵育3小时以形成aLHR复合物；随后在34℃与荧光标记的抗小鼠免疫球蛋白进行第二次孵育，34℃这个温度允许内化发生。在34℃下15分钟内即可检测到细胞质荧光染色；60分钟后这种染色清晰可见。任何时候都未观察到细胞核染色。采用这种方法，当用次最大剂量的LH刺激细胞时，也能够追踪未被占据的受体的命运。结果表明，LH与其20%的受体相互作用会导致游离受体位点发生微聚集、斑块形成、帽化和内化。结果进一步证明，处于帽化状态的受体细胞对第二次LH刺激的敏感性较低，这表明在这种状态下受体不再与腺苷酸环化酶系统偶联。
