Weber H W, Chung F Z, Day K, Appleman M M
J Cyclic Nucleotide Protein Phosphor Res. 1986;11(5):345-54.
The intact rat adipocyte was used to investigate the possibility of common intermediates in the insulin stimulation of cyclic AMP phosphodiesterase and the beta-adrenergic/adenosine regulation of adenylate cyclase. A five minute incubation of the isolated adipocytes with insulin produced a 50-100% increase in the phosphodiesterase activity found in the particulate fraction of homogenates. The insulin stimulation was not impaired by the presence of either agonist or antagonists of the inhibitory adenosine receptor which acts on adenylate cyclase. Phosphodiesterase activation by insulin was also observable above the level of stimulation produced by the beta-adrenergic agent isoproterenol and forskolin. The validity of the enzyme activity measurements was supported by measurements of the hormonal actions on cyclic AMP levels within the cells. Possible crossover between the adenylate cyclase and phosphodiesterase regulation systems at a post-receptor site was investigated using adipocytes exposed to bacterial toxins specific for the modification of guanine nucleotide binding proteins. Both cholera toxin, which irreversibly activates Gs and pertussis toxin which inactivates Gi caused some stimulation of the phosphodiesterase activity and suppressed activation by isoproterenol, but neither toxin prevented the insulin stimulation of cyclic AMP phosphodiesterase. These results suggest, while common components may participate in the beta-adrenergic stimulation of both adenylate cyclase and phosphodiesterase, the mechanism of insulin activation of the phosphodiesterase does not involve the components of adenylate cyclase regulation.
完整的大鼠脂肪细胞被用于研究胰岛素刺激环磷酸腺苷磷酸二酯酶以及β-肾上腺素能/腺苷调节腺苷酸环化酶过程中共同中间体的可能性。将分离的脂肪细胞与胰岛素孵育五分钟后，匀浆颗粒部分中的磷酸二酯酶活性增加了50%-100%。胰岛素刺激不受作用于腺苷酸环化酶的抑制性腺苷受体的激动剂或拮抗剂存在的影响。胰岛素对磷酸二酯酶的激活作用在β-肾上腺素能药物异丙肾上腺素和福斯可林产生的刺激水平之上也可观察到。细胞内环磷酸腺苷水平的激素作用测量结果支持了酶活性测量的有效性。使用暴露于对鸟嘌呤核苷酸结合蛋白修饰具有特异性的细菌毒素的脂肪细胞，研究了腺苷酸环化酶和磷酸二酯酶调节系统在受体后位点可能的交叉作用。不可逆激活Gs的霍乱毒素和使Gi失活的百日咳毒素都引起了磷酸二酯酶活性的一些刺激，并抑制了异丙肾上腺素的激活作用，但两种毒素都不能阻止胰岛素对环磷酸腺苷磷酸二酯酶的刺激。这些结果表明，虽然共同成分可能参与了β-肾上腺素能对腺苷酸环化酶和磷酸二酯酶的刺激，但胰岛素激活磷酸二酯酶的机制并不涉及腺苷酸环化酶调节的成分。
