Mishra R K, Feltham L A
Can J Biochem. 1975 Jan;53(1):70-8. doi: 10.1139/o75-011.
The results of steroid hormone stimulation of aggregate RNA polymerase ?activity in kidney can be interpreted in terms of either template or enzyme alterations. In order to discover the effect of aldosterone on enzyme or DNA template, the RNA polymerases were purified from kidney nuclei of normal, adrenalectomized or adrenalectomized plus aldosterone treated rats and the activity was determined using different sources of DNA. It was found that the DNA from aldosterone treated rats was transcribed more efficiently than from other sources. Aldosterone does not seem to have a direct effect on the RNA polymerase. Fractionation of ([14-C]aldosterone injected) kidney chromatin revealed the presence of radioactivity in the non-histone acidic proteins and DNA, suggesting the possible binding of aldosterone or aldosterone-receptor complex to these chromatin fractions which may result in enhanced template activity. Turnover of RNA was also studied in various subcellular fractions: nuclei, mitochondria, rough endoplasmic reticulum, smooth endoplasmic reticulum, polysomes, ribosomes and sRNA, in normal, adrenalectomized, and adrenalectomized plus adrenocortical hormone treated rat kidney, by following the loss of radioactivity after a single injection of [14-C]-orotic acid. Daily administration of aldosterone or deoxycorticosterone reversed the effects of adrenalectomy. Daily administration of corticosterone was without effect.
甾体激素对肾中聚合RNA聚合酶活性的刺激结果，可以从模板或酶的改变方面来解释。为了探究醛固酮对酶或DNA模板的影响，从正常、肾上腺切除或肾上腺切除加醛固酮处理的大鼠的肾细胞核中纯化RNA聚合酶，并使用不同来源的DNA测定其活性。结果发现，来自醛固酮处理大鼠的DNA比其他来源的DNA转录效率更高。醛固酮似乎对RNA聚合酶没有直接影响。对（注射了[14-C]醛固酮的）肾染色质进行分级分离，结果显示在非组蛋白酸性蛋白和DNA中存在放射性，这表明醛固酮或醛固酮-受体复合物可能与这些染色质组分结合，这可能导致模板活性增强。还通过单次注射[14-C]乳清酸后追踪放射性的损失，研究了正常、肾上腺切除以及肾上腺切除加肾上腺皮质激素处理的大鼠肾中各个亚细胞组分（细胞核、线粒体、粗面内质网、滑面内质网、多核糖体、核糖体和小RNA）中的RNA周转情况。每天给予醛固酮或脱氧皮质酮可逆转肾上腺切除的影响。每天给予皮质酮则没有效果。
