Oxytocin stimulates myometrial guanosine triphosphatase and phospholipase-C activities via coupling to G alpha q/11.
Oxytocin stimulates myometrial guanosine triphosphatase and phospholipase-C activities via coupling to G alpha q/11.
复制标题
DOI：
10.1210/endo.136.4.7895660
复制
发表时间：
1995-04
期刊：
影响因子：
4.8
通讯作者：
C. Ku;Ansha Qian;Yeshao Wen;Khursheed Anwer;Barbara M. Sanborn
中科院分区：
文献类型：
--
作者：
C. Ku;Ansha Qian;Yeshao Wen;Khursheed Anwer;Barbara M. Sanborn
催产素刺激子宫肌层中磷脂酰肌醇的更新。为了阐明这种偶联机制是否涉及催产素受体与GTP结合蛋白的相互作用，我们检测了催产素对大鼠和人子宫肌膜鸟苷三磷酸酶(GTPase)和磷脂酶-C活性的刺激作用。催产素持续地刺激GTP酶和磷脂酶-C的活性，这两种刺激都被针对GTP结合蛋白GαQ和Gα11的羧基末端的抗体减弱。用抗原肽预先孵育抗体可以逆转这种抑制。催产素受体特异性激动剂[Thr4，Gly7]催产素对GTP酶和磷脂酶-C活性均有刺激作用，并可被抗GαQ/11抗体所抑制。GTP结合蛋白GαQ和Gα11以及磷脂酶Cβ3亚型在子宫肌膜中均有表达。这些结果表明，催产素对子宫肌层磷脂酶-C活性的刺激是通过Gαq、Gα11或一种密切相关的GTP结合蛋白介导的，可能与磷脂酶Cβ偶联。
Oxytocin stimulates phosphoinositide turnover in myometrium. To elucidate whether the coupling mechanism involves the interaction of oxytocin receptor with GTP-binding proteins, we examined oxytocin stimulation of guanosine triphosphatase (GTPase) activity and phospholipase-C activity in rat and human myometrial membranes. Oxytocin consistently stimulated both GTPase and phospholipase-C activities, and both stimulations were attenuated by an antibody directed against the carboxyl-terminals of the GTP-binding proteins, G alpha q and G alpha 11. Neutralization of the antibody by preincubation with antigenic peptide reversed this inhibition. [Thr4,Gly7]oxytocin, a specific oxytocin receptor agonist, stimulated both GTPase and phospholipase-C activities, and the stimulations were also inhibited by anti-G alpha q/11 IgG. Immunoreactive GTP-binding proteins, G alpha q and G alpha 11, and phospholipase-C beta 3 isoforms were present in myometrial membranes. These results indicate that stimulation of phospholipase-C activity by oxytocin in myometrium is mediated via G alpha q, G alpha 11, or a closely related GTP-binding protein, probably coupling to phospholipase-C beta.