INTERNALIZATION; INTRACELLULAR BINDING OF GONADOTROPIN

牛的细胞核、溶酶体、粗面内质网和高尔基体以及质膜 黄体含有125 I-人绒毛膜特异性结合位点 促性腺激素（125 I-hCG）。 125 I-hCG的内化与肿瘤的发生有关， 受体以完整的形式存在于所有上述细胞内细胞器中。 125 I-hCG降解不是125 I-hCG的主要后果 在孵育的前2小时期间的内化。 这些发现可能 至少部分代表促性腺激素的细胞内途径 受体合成和再循环。 然而，这条道路既不是 促性腺激素受体明确记录，数据也没有 存在表明细胞内结合位点没有功能性 意义 内化促性腺激素的功能意义 与细胞内细胞器的结合由以下建议，a） 内化125 I-hCG结合的细胞内细胞器的多样性 B）与某些细胞内细胞器的结合非常高（即，Golgi） c）核联合和d）缺乏高水平的激素 在孵育的前2小时内降解。 为了评价其功能意义，我们将研究直接hCG 对核RNA合成、RNA聚合酶活性、染色质的影响 密度和溶解度变化，mRNA的退出，核苷三磷酸酶 活性、磷酸化和去磷酸化、125 I-hCG结合和 黄体细胞质内化及其对hCG和 环腺苷酸。 hCG对溶酶体、粗面内质网和高尔基体的直接作用 酶活性，磷酸化和去磷酸化将被研究 沿着测定侧性（池或细胞质）， 受体和分离的溶酶体降解激素的能力和/或 受体。 将运行相应的细胞器对照（未添加激素） 同步 质膜也将被包括在一些 实验进行比较。 所看到的任何影响都将扩展到包括 激素和组织特异性及环磷酸腺苷模拟可能性 hCG。 将寻求体外观察到的效应的体内确认 使用超排卵的老鼠。 无论是激素的浓度， 所看到的效果将对应于生理水平和明显的 激素结合的解离常数将被严格地简化。 所获得的结果可能会开辟新的和令人兴奋的可能性， 促性腺激素的作用，这是以前从未想过的。

Nuclei, lysosomes, rough ER and Golgi as well as plasma membranes of bovine corpora lutea contain specific binding sites for 125I-human chorionic gonadotropin (125I-hCG). The internalized 125I-hCG associated with the receptors in all of the above intracellular organelles in an intact form. 125I-hCG degradation is not a primary consequence of 125I-hCG internalization during the first 2 hrs of incubation. These findings may represent, at least in part, the intracellular pathway of gonadotropin receptor synthesis and recycling. However, this pathway is neither documented unequivocally for gonadotropin receptors, nor does the data exist to show that the intracellular binding sites have no functional significance. Functional significance for internalized gonadotropin binding to the intracellular organelles is suggested by the following, a) diversity of intracellular organelles to which internalized 125I-hCG binds b) very high binding to some of the intracellular organelles (i.e., Golgi) c) nuclear association and d) the lack of high levels of hormone degradation during the first 2 hrs of incubation. To evaluate the functional significance, we will study the direct hCG effects on nuclear RNA synthesis, activity of RNA polymerases, chromatin density and solubility changes, exit of mRNA, nucleoside triphosphatase activity, phosphorylation and dephosphorylation, 125I-hCG binding and internalization in luteal cytoplasts and their responsiveness to hCG and cyclic AMP. The direct hCG effects on lysosomal, RER and Golgi intrinsic enzyme activities, phosphorylation and dephosphorylation will be studied along with determination of sidedness (cisternal or cytoplasmic) of receptors and capability of isolated lysosomes to degrade hormone and/or receptors. Corresponding organelle controls (no hormone added) will be run simultaneously. Plasma membranes will also be included in some of the experiments for comparison. Any effects seen will be extended to include hormonal and tissue specificity and possibility of cyclic AMP mimicking hCG. In vivo confirmation of observed effects in vitro will be sought using superovulated rats. Whether the concentration of hormone at which the effects are seen will correspond to physiological levels and apparent dissociation constant for hormone binding will be closely scruntinized. The results obtained may open up new and exciting possibilities in gonadotropin action which were never thought to exist before.