Schwartz J P, Passonneau J V
Proc Natl Acad Sci U S A. 1974 Oct;71(10):3844-8. doi: 10.1073/pnas.71.10.3844.
Long-term regulation of the cyclic nucleotide phosphodiesterase of the C-6 rat glioma cell line has been studied. Both the low K(m) and high K(m) activities can be induced by elevation of intracellular cyclic AMP levels following either dibutyryl cyclic AMP or norepinephrine treatment of the cells. The enzymes are maximally induced by 3-4 hr. The presence of either cycloheximide or actinomycin D prevents induction by either dibutyryl cyclic AMP or norepinephrine. Evidence is presented that the norepinephrine effect is mediated by the beta-catecholamine receptor. The increased phosphodiesterase activity causes a partial refractoriness to a second challenge with norepinephrine, which can be overcome by blockade of the induction with cycloheximide. The results suggest that just as short-term regulation of cyclic AMP levels occurs via changes in the rates of synthesis or degradation, long-term alterations of the system may also involve either the adenylate cyclase or the phosphodiesterase.
对C-6大鼠胶质瘤细胞系中环核苷酸磷酸二酯酶的长期调节进行了研究。在用二丁酰环磷腺苷或去甲肾上腺素处理细胞后,细胞内环磷腺苷水平升高可诱导低Km和高Km活性。这些酶在3-4小时时被最大程度地诱导。放线菌酮或放线菌素D的存在可阻止二丁酰环磷腺苷或去甲肾上腺素的诱导。有证据表明去甲肾上腺素的作用是由β-儿茶酚胺受体介导的。磷酸二酯酶活性的增加导致对去甲肾上腺素的第二次刺激产生部分不应性,这可通过用放线菌酮阻断诱导来克服。结果表明,正如环磷腺苷水平的短期调节是通过合成或降解速率的变化发生的一样,该系统的长期改变也可能涉及腺苷酸环化酶或磷酸二酯酶。