Rousseau G G, Martial J, de Visscher M
Eur J Biochem. 1976 Jul 15;66(3):499-506. doi: 10.1111/j.1432-1033.1976.tb10575.x.
We have examined whether glucocorticoids control the activity and (or) the subcellular distribution of protein kinase dependent on cyclic AMP (adenosine 3':5'-monophosphate), since they influence cyclic-AMP-dependent responses to other hormones. Protein kinase activity was determined in rat liver homogenates and subcellular fractions, nuclear, large granular, microsomal and supernatant obtained by differential sedimentation in 0.25 M sucrose. 63% of the tissue protein kinase activity detected in absence of cyclic AMP reside in the particulate fractions. Upon addition of exogenous cyclic AMP, protein kinase activity is stimulated 1.8, 1.2, 1.2 and 4.5-fold in nuclear, large granular, microsomal and supernatant fractions, respectively. Under these conditions, 66% of tissue activity are found in the supernatant fraction. The activity sensitive to exogenous cyclic AMP resolves into a major (84%) cytosoluble and a minor (16%) nucleomicrosomal component. The latter activity resists elution with isotonic saline and is increased in the presence of Triton X-100. Three groups of rats were studied: control and adrenalectomized with or without cortisol treatment. In whole liver homogenates, both protein kinase activity detected in absence of exogenous cyclic AMP and sensitivity of the enzyme to cyclic AMP were comparable in all groups. Moreover, the distribution patterns of proteins kinase activity amoung the fractions were essentially the same in all groups of animals, whether or not particles had been treated with Triton X-100. Finally, in cell-free experiments, glucocorticoids alone or in combination with their intracellular receptor did not modify protein kinase activity of rat liver. Thus the results reported do not support the possibility that glucocorticoids influence cyclic AMP-dependent protein kinase in rat liver. Yet, this study provides data, not available before, on subcellular distribution of this enzyme in rat liver.
我们已经研究了糖皮质激素是否控制依赖环磷酸腺苷（腺苷3':5'-单磷酸）的蛋白激酶的活性和（或）亚细胞分布情况，因为它们会影响对其他激素的环磷酸腺苷依赖性反应。在大鼠肝脏匀浆和亚细胞组分（通过在0.25M蔗糖中进行差速离心获得的细胞核、大颗粒、微粒体和上清液）中测定蛋白激酶活性。在不存在环磷酸腺苷的情况下检测到的组织蛋白激酶活性，有63%存在于颗粒组分中。加入外源性环磷酸腺苷后，细胞核、大颗粒、微粒体和上清液组分中的蛋白激酶活性分别被刺激1.8倍、1.2倍、1.2倍和4.5倍。在这些条件下，66%的组织活性存在于上清液组分中。对外源性环磷酸腺苷敏感的活性可分为一个主要的（84%）可溶细胞质组分和一个次要的（16%）核微粒体组分。后者的活性在等渗盐溶液中不能洗脱，并且在Triton X-100存在时会增加。研究了三组大鼠：对照组、肾上腺切除组以及肾上腺切除后接受或未接受皮质醇治疗的组。在全肝匀浆中，所有组中在不存在外源性环磷酸腺苷时检测到的蛋白激酶活性以及该酶对环磷酸腺苷的敏感性相当。此外，无论颗粒是否用Triton X-100处理，所有动物组中蛋白激酶活性在各组分之间的分布模式基本相同。最后，在无细胞实验中，单独的糖皮质激素或与它们的细胞内受体联合使用都不会改变大鼠肝脏的蛋白激酶活性。因此，所报道的结果不支持糖皮质激素影响大鼠肝脏中环磷酸腺苷依赖性蛋白激酶的可能性。然而，这项研究提供了此前未曾有过的关于该酶在大鼠肝脏中亚细胞分布的数据。
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