Rossier B C, Wilce P A, Inciardi J F, Yoshimura F K, Edelman I S
Am J Physiol. 1977 May;232(5):C174-9. doi: 10.1152/ajpcell.1977.232.5.C174.
Previous studies showed that aldosterone augments transepithelial active Na+ transport and the incorporation of [3H]uridine into polyadenylated RNA (poly(A)(+)-RNA) (putatively mRNA) early in the latent period. Soon thereafter, incorporation of [methyl-14C] groups, as well as [3H]uridine into rRNA is also increased. To evaluate the role of rRNA in mineralocorticoid action, the inhibitor 3'-deoxycytidine was used in studies on the urinary bladder of the toad Bufo marinus. 3'-deoxycytidine suppressed the incorporation of [methyl-14C] and [3H]uridine into nuclear precursors of rRNA and subunits of cytoplasmic rRNA. In contrast, 3'-deoxycytidine inhibited incorporation of ]3H]uridine into cytoplasmic poly(A)(+)-RNA minimally. In control experiments, 3'-deoxycytidine had no significant effect on Na+ transport, measured as the short-circuit current (scc), when given alone. 3'-Deoxycytidine also had no significant effect on the aldosterone-dependent increase in scc. In the presence of 3'-deoxycytidine, aldosterone enhanced both the scc and the incorporation of [3H]uridine into poly(A)(+)-RNA significantly. We conclude that during the first 3 h, the mineralocorticoid action of aldosterone is not sensitive to inhibition of rRNA synthesis. Previous studies, however, implicate mRNA synthesis in this early response.
先前的研究表明，醛固酮在潜伏期早期可增强上皮细胞的主动钠转运以及[3H]尿苷掺入多聚腺苷酸化RNA（聚腺苷酸（+）-RNA，推测为信使核糖核酸）。此后不久，[甲基-14C]基团以及[3H]尿苷掺入核糖体核糖核酸也增加。为了评估核糖体核糖核酸在盐皮质激素作用中的作用，在海蟾蜍膀胱的研究中使用了抑制剂3'-脱氧胞苷。3'-脱氧胞苷抑制了[甲基-14C]和[3H]尿苷掺入核糖体核糖核酸的核前体以及细胞质核糖体核糖核酸的亚基。相比之下，3'-脱氧胞苷对[3H]尿苷掺入细胞质聚腺苷酸（+）-RNA的抑制作用最小。在对照实验中，单独给予3'-脱氧胞苷时，对以短路电流（scc）衡量的钠转运没有显著影响。3'-脱氧胞苷对醛固酮依赖性的短路电流增加也没有显著影响。在存在3'-脱氧胞苷的情况下，醛固酮显著增强了短路电流以及[3H]尿苷掺入聚腺苷酸（+）-RNA的量。我们得出结论，在最初3小时内，醛固酮的盐皮质激素作用对核糖体核糖核酸合成的抑制不敏感。然而，先前的研究表明信使核糖核酸合成参与了这一早期反应。
