Hui K K, Yu J L
Department of Medicine, UCLA School of Medicine 90024.
Life Sci. 1990;47(4):269-81. doi: 10.1016/0024-3205(90)90584-e.
The objective of the present study was to investigate the roles of protein kinase A and/or C in agonist-induced beta adrenoceptor activation in intact human lymphocytes. LYmphocytes from healthy subjects were incubated with isoproterenol and phosphodiesterase inhibitor (IBMX, 1.0 mM) after 20 minutes of preincubation with (or without) various compounds possessing protein kinase A and/or C inhibitory activities. These compounds included the relatively selective protein kinase C (PK-C) inhibitors (W-7, calmidazolium, polymyxin B, neomycin, tamoxifen and clomiphene), purified protein inhibitors of protein kinase A (PK-A) (obtained synthetically, or purified from bovine hearts and porcine hearts) and the two compounds (H-7, H-9), which have been found to inhibit both PK-A and PK-C. The results showed that all PK-C inhibitors alone decreased cellular basal cAMP levels while inhibitors of PK-A as well as both H-7 and H-9 increased basal cAMP levels in a dose dependent manner at certain concentrations. All inhibitors studied potentiated isoproterenol-induced cAMP accumulation. The protein kinase A and C inhibitor, H-7, also potentiated PGE1 (but not forskolin)-induced cAMP accumulation. In contrast, the protein kinase C activator, PMA, inhibited isoproterenol- and PGE1- (but not forskolin) induced cAMP accumulation. These data suggest that the potentiating effects of PK-A and/or C inhibitors may be related to the inhibition of PK-A and/or PK-C, both of which have been shown to be involved in beta 2 adrenoceptor desensitization and phosphorylation.
本研究的目的是探讨蛋白激酶A和/或C在完整人淋巴细胞中激动剂诱导的β肾上腺素能受体激活中的作用。在与（或不与）具有蛋白激酶A和/或C抑制活性的各种化合物预孵育20分钟后，将健康受试者的淋巴细胞与异丙肾上腺素和磷酸二酯酶抑制剂（异丁基甲基黄嘌呤，1.0 mM）一起孵育。这些化合物包括相对选择性的蛋白激酶C（PK-C）抑制剂（W-7、氯米帕明、多粘菌素B、新霉素、他莫昔芬和克罗米芬）、蛋白激酶A（PK-A）的纯化蛋白抑制剂（通过合成获得，或从牛心和猪心中纯化）以及已发现可抑制PK-A和PK-C的两种化合物（H-7、H-9）。结果表明，单独使用所有PK-C抑制剂均会降低细胞基础cAMP水平，而PK-A抑制剂以及H-7和H-9在某些浓度下以剂量依赖性方式增加基础cAMP水平。所有研究的抑制剂均增强了异丙肾上腺素诱导的cAMP积累。蛋白激酶A和C抑制剂H-7也增强了PGE1（但不是福斯高林）诱导的cAMP积累。相反，蛋白激酶C激活剂PMA抑制异丙肾上腺素和PGE1（但不是福斯高林）诱导的cAMP积累。这些数据表明，PK-A和/或C抑制剂的增强作用可能与PK-A和/或PK-C的抑制有关，这两者均已被证明与β2肾上腺素能受体脱敏和磷酸化有关。
