Tewari S, Duerbeck N B, Noble E P
Res Commun Chem Pathol Pharmacol. 1978 Nov;22(2):401-18.
Recent laboratory endeavors have been primarily concerned with determining the effects of chronic ethanol ingestion on cerebral RNA metabolism within the inner mitochondrial membrane (IMM). Toward this goal, a series of experiments were carried out by determining the RNA and protein synthetic activity of the organelle. Brain mitochondria actively incorporated [5-3H]orotic acid into RNA under in vivo conditions. In addition, data showed that a major portion of the radioactivity present in the cold TCA insoluble residue from labeled intact mitochondria could be recovered in the digitonin treated purified IMM fraction. Maximum incorporation of [5-3H]orotic acid into RNA took place within 24 hrs followed by a rapid decline in activity on the 5th day of the pulse in both 'control' and 'ethanol' ingesting rats. Data revealed that ethanol ingestion affected the degree of incorporation of labeled RNA precursor into the mitochondrial RNA fraction. The observed effect was in the form of inhibition and was dependent on the duration of the initial pulse. Thus, while at earlier time points a decreased incorporation of the precursor into mitochondrial RNA was obtained in the ethanol imbibing rats, the inhibition was not observed when the pulse time was extended to 5 days. Such results indicate the possibility of a rapid turnover rate for the brain mitochondrial RNA with the 'ethanol' group having a faster rate of turnover when compared to the 'control' group.
近期的实验室研究主要关注慢性乙醇摄入对内线粒体膜（IMM）内脑RNA代谢的影响。为实现这一目标，通过测定该细胞器的RNA和蛋白质合成活性进行了一系列实验。脑线粒体在体内条件下能将[5-³H]乳清酸积极地掺入RNA中。此外，数据表明，标记完整线粒体的冷三氯乙酸不溶性残渣中存在的大部分放射性可在经洋地黄皂苷处理的纯化IMM组分中回收。在“对照”和“乙醇”摄入大鼠中，[5-³H]乳清酸掺入RNA的最大值在24小时内出现，随后在脉冲第5天活性迅速下降。数据显示，乙醇摄入影响标记RNA前体掺入线粒体RNA组分的程度。观察到的效应表现为抑制作用，且取决于初始脉冲的持续时间。因此，虽然在早期时间点，乙醇摄入大鼠中线粒体RNA前体的掺入量减少，但当脉冲时间延长至5天时未观察到抑制作用。这些结果表明脑线粒体RNA可能具有快速周转率，与“对照”组相比，“乙醇”组的周转率更快。
