Activation of adenylate cyclase in bovine corpus-luteum membranes by human choriogonadotropin, guanine nucleotides and NaF.
Activation of adenylate cyclase in bovine corpus-luteum membranes by human choriogonadotropin, guanine nucleotides and NaF.
复制标题
人绒毛膜促性腺激素、鸟嘌呤核苷酸和 NaF 激活牛黄体膜中的腺苷酸环化酶。
DOI：
10.1042/bj1980631
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发表时间：
1981
期刊：
影响因子：
--
通讯作者：
D. Stansfield
中科院分区：
文献类型：
--
作者：
N. Lydon;J. L. Young;D. Stansfield
1.用人绒毛膜促性腺激素预先孵育黄体膜会形成腺苷环化酶的激活状态，这种激活状态不会被洗涤逆转，并且只受鸟嘌呤核苷酸的限制，而与GTP预先孵育只会产生部分激活的腺苷环化酶，在测定过程中需要同时存在GTP和人绒毛膜促性腺激素才能显示最大的活性。2.用GTP和人绒毛膜促性腺激素预先孵育黄体膜，并不能协同增加黄体膜的耐洗涤活性。3.在腺苷环化酶孵育过程中，预先用GTP和激素孵育的黄体膜环磷酸腺苷的合成速率降低，而在腺苷环化酶孵育过程中加入GTP则逆转了这种下降。4.在没有鸟嘌呤核苷酸和激素的情况下预先孵育的膜，在GTP存在的情况下，出现了环磷酸腺苷合成的“爆发期”，在实验中出现了含有p[NH]ppg(鸟苷5‘-[β，伽马亚胺]三磷酸)的a’滞后‘相。人绒毛膜促性腺激素和任一种核苷酸的存在消除了单独使用鸟嘌呤核苷酸观察到的曲线度。5.p[NH]ppg单独或与人绒毛膜促性腺激素共同孵育可持续激活黄体腺苷环化酶，p[NH]ppg单独作用70min后激活仍在增加，而p[NH]ppg与激素联合作用在10min内基本完全激活。6.用p[NH]ppg预温育后部分激活的黄体腺苷环化酶在加入p[NH]ppg后活性略有增加，但在p[NH]ppg和激素的作用下表现得更为明显。单独的人绒毛膜促性腺激素不会进一步增加部分刺激制剂的活性，除非在测定孵育中也加入p[NH]ppg。7.在p[NH]ppg存在下，GTP降低了部分预活化的膜上腺苷环化酶的活性；当GTP和激素同时存在时，活性的下降更明显。8.结果表明，人绒毛膜促性腺激素或p[NH]ppg可诱导体外黄体膜上腺苷环化酶处于稳定的激活状态，而在p[NH]ppg存在下，激素可加速鸟嘌呤核苷酸结合后的活动。预先接触GTP不能稳定激活黄体腺苷环化酶。讨论了GTP酶活性和激素促进的鸟嘌呤核苷酸交换在黄体腺苷环化酶活性调节中的作用。
1. Preincubation of luteal membranes with human choriogonadotropin results in the formation of an activated state of adenylate cyclase which is not reversed by washing and which is limited only by the absence of guanine nucleotides, whereas preincubation with GTP yields only a partially activated adenylate cyclase which requires the presence of both GTP and human choriogonadotropin during assay to demonstrate maximal activity. 2. Preincubation of luteal membranes with GTP and human choriogonadotropin does not lead to a synergistic increase in wash-resistant activity. 3. Luteal membranes that had been preincubated with GTP and hormone exhibited a decreasing rate of cyclic AMP synthesis during the adenylate cyclase assay incubation; addition of GTP during the assay incubation reversed the decrease. 4. Membranes that had been preincubated in the absence of guanine nucleotide and hormone showed a ;burst' phase of cyclic AMP synthesis when GTP was present in the assay incubation and a ;lag' phase with p[NH]ppG (guanosine 5'-[beta,gamma-imido]triphosphate) present in the assay. The presence of human choriogonadotropin with either nucleotide in the assay incubation eliminated the curvatures in plots observed with guanine nucleotides alone. 5. Luteal adenylate cyclase was persistently activated by preincubation with p[NH]ppG alone or in combination with human choriogonadotropin; the activation caused by p[NH]ppG alone was still increasing after 70min of preincubation, whereas that caused by p[NH]ppG in the presence of hormone was essentially complete within 10min of preincubation. 6. Luteal adenylate cyclase that had been partially preactivated by preincubation with p[NH]ppG was slightly increased in activity by the inclusion of further p[NH]ppG in the adenylate cyclase assay incubation, but more so with p[NH]ppG and hormone. Human choriogonadotropin alone caused no further increase in the activity of the partially stimulated preparation unless p[NH]ppG was also added to the assay incubation. 7. GTP decreased the activity of adenylate cyclase in membranes that had been partially preactivated in the presence of p[NH]ppG; the decrease in activity was greater when GTP and hormone were present simultaneously in the assay. 8. The results indicate that stable activation states of adenylate cyclase can be induced by preincubation of luteal membranes in vitro with human choriogonadotropin or p[NH]ppG, and that in the presence of p[NH]ppG the hormone may accelerate events subsequent to guanine nucleotide binding. Stable activation of luteal adenylate cyclase by prior exposure to GTP is not achieved. The involvement of GTPase activity and of hormone-promoted guanine nucleotide exchange in the modulation of luteal adenylate cyclase activity is discussed.