Staehelin M, Müller P, Portenier M, Harris A W
J Cyclic Nucleotide Protein Phosphor Res. 1985;10(1):55-64.
beta-Adrenergic receptors were determined in sixteen cultured tumor cell lines of T- and B-lymphoid derivation by the binding of the hydrophilic ligand [3H]CGP-12177. The number of receptors per cell varied from less than a hundred to over three thousand. Intracellular cAMP responses to isoproterenol and forskolin were measured for seven cell lines possessing a range of receptor numbers. No direct relationship was found between the isoproterenol-induced elevation of cAMP and the receptor number, and forskolin-induced increases in cAMP varied by more than 100-fold between cell lines. Adenylate cyclase activity was also measured in membrane preparations from the seven cell lines. The T-lymphoma line WEHI-22, the line with the highest receptor number (3700 per cell), showed very little response to any stimulatory agent. With the other four cell lines possessing receptors, the membrane-bound adenylate cyclase activity evoked by isoproterenol relative to that evoked by forskolin was found to be proportional to the number of receptors per cell. The number of receptors thus seems to determine the proportion of the inherent adenylate cyclase that can be activated by a beta-adrenergic agent. The levels of adenylate cyclase induced in membranes by GppNHp and by fluoride, relative to those induced by forskolin, were substantially higher with some cell lines than with others. These data and the results from WEHI-22 cells indicate that lymphoid cell lines differ in their content of functional C and N proteins.
通过亲水性配体[3H]CGP - 12177的结合，测定了16种T淋巴细胞和B淋巴细胞来源的培养肿瘤细胞系中的β - 肾上腺素能受体。每个细胞的受体数量从不到一百个到超过三千个不等。对具有一系列受体数量的7个细胞系，测量了细胞内cAMP对异丙肾上腺素和福斯高林的反应。未发现异丙肾上腺素诱导的cAMP升高与受体数量之间存在直接关系，并且细胞系之间福斯高林诱导的cAMP增加相差超过100倍。还在这7个细胞系的膜制剂中测量了腺苷酸环化酶活性。T淋巴瘤细胞系WEHI - 22，受体数量最高（每个细胞3700个），对任何刺激剂的反应都非常小。对于其他四个具有受体的细胞系，发现异丙肾上腺素诱发的膜结合腺苷酸环化酶活性相对于福斯高林诱发的活性与每个细胞的受体数量成正比。因此，受体数量似乎决定了可被β - 肾上腺素能剂激活的固有腺苷酸环化酶的比例。一些细胞系中，相对于福斯高林诱导的水平，GppNHp和氟化物诱导的膜中腺苷酸环化酶水平明显高于其他细胞系。这些数据以及WEHI - 22细胞的结果表明，淋巴细胞系在其功能性C蛋白和N蛋白的含量上存在差异。
