Anand-Srivastava M B, Gutkowska J, Cantin M
Neuroendocrinology. 1985 Aug;41(2):113-8. doi: 10.1159/000124163.
An adenosine-sensitive adenylate cyclase has been demonstrated in anterior pituitary cultured cells in the present studies. N-ethylcarboxamideadenosine (NECA), L-N6-phenylisopropyladenosine (PIA), and 5'-N-methylcarboxamideadenosine (MECA), all stimulated adenylate cyclase in a concentration-dependent manner in the order of potency NECA greater than PIA greater than MECA. Adenosine showed a biphasic effect on adenylate cyclase: stimulation at lower and inhibition at higher concentrations, whereas 2'-deoxyadenosine only inhibited adenylate cyclase in a concentration-dependent manner. The stimulatory effect of NECA on adenylate cyclase was dependent on metal ion concentrations and was blocked by 3-isobutyl-1-methylxanthine and 8-phenyltheophylline. Various agonists such as isoproterenol, prostaglandins (PGE1), vasoactive intestinal peptide, corticotropin-releasing factor, NaF, and forskolin, all stimulated adenylate cyclase to various degrees. The stimulatory effect of vasoactive intestinal peptide and corticotropin-releasing factor on adenylate cyclase was found to be almost additive with the stimulation exerted by NECA. These data indicate the presence of adenosine stimulatory receptors ('Ra') in anterior pituitary which are coupled to adenylate cyclase. It is possible that adenosine may act as one of the important regulators to regulate and/or modulate the effects of agents/factors in the release of pituitary hormones.
在本研究中，已在前脑垂体培养细胞中证实了一种对腺苷敏感的腺苷酸环化酶。N-乙基甲酰胺腺苷（NECA）、L-N6-苯基异丙基腺苷（PIA）和5'-N-甲基甲酰胺腺苷（MECA）均以浓度依赖性方式刺激腺苷酸环化酶，其效力顺序为NECA＞PIA＞MECA。腺苷对腺苷酸环化酶表现出双相作用：低浓度时刺激，高浓度时抑制，而2'-脱氧腺苷仅以浓度依赖性方式抑制腺苷酸环化酶。NECA对腺苷酸环化酶的刺激作用取决于金属离子浓度，并被3-异丁基-1-甲基黄嘌呤和8-苯基茶碱阻断。各种激动剂，如异丙肾上腺素、前列腺素（PGE1）、血管活性肠肽、促肾上腺皮质激素释放因子、NaF和福斯高林，均不同程度地刺激腺苷酸环化酶。发现血管活性肠肽和促肾上腺皮质激素释放因子对腺苷酸环化酶的刺激作用与NECA所产生的刺激作用几乎具有相加性。这些数据表明在前脑垂体中存在与腺苷酸环化酶偶联的腺苷刺激受体（“Ra”）。腺苷有可能作为重要的调节因子之一来调节和/或调制垂体激素释放过程中各种因子的作用。
