豚鼠全身X线照射对肝脏核糖核酸合成的影响。

The effect of whole-body x-irradiation of guinea pigs on liver ribonucleic acid synthesis.

作者信息

Hidvégi E J, Bölöni E, Holland J, Antoni F, Várterész V

出版信息

Biochem J. 1970 Feb;116(3):503-14. doi: 10.1042/bj1160503.

DOI:10.1042/bj1160503

PMID:5435693

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC1185388/

Abstract

Liver RNA synthesis was studied within 24h after whole-body X-irradiation of guinea pigs that had been starved for 22-24h. 2. Microsomal RNA was labelled in vivo for 3h with [(14)C]orotic acid and the isolated labelled RNA was fractionated by sucrose-density-gradient centrifugation. Incorporation was 50-100% higher between 3 and 12h after 2000rd X-irradiation and at 22h was not elevated any further. Whole nuclear RNA was labelled with [(14)C]orotic acid for 15min. At 5h after irradiation the incorporation showed a 50-100% increase. Incorporation increased in all types of RNA studied. 3. The RNA phosphorus/DNA phosphorus ratio of whole liver gradually increased after X-irradiation. Maximal increase was found between 24 and 36h, which corresponds to a value about 40% above that of the starved control. The RNA phosphorus content of isolated ribonucleoproteins obtained from various cell fractions of the liver was similarly increased after X-irradiation. 4. Liver microsomes were obtained from X-irradiated and control animals. Microsomes were incubated in vitro with [(14)C]phenylalanine in the presence and absence of polyuridylic acid. After the incubation the microsomes were fractionated by sucrose-density-gradient centrifugation. The polyuridylic acid enhancement was twice as great in the microsomes of the control preparation as in the irradiated one. The experiment demonstrated a higher saturation of microsomes by endogenous messenger after X-irradiation. 5. RNA polymerase activity of the purified nuclear preparation was assayed. The activity of the Mg(2+)-dependent RNA polymerase activity was 50 and 200% respectively above the control values at 6 and 9h after X-irradiation. 6. Animals were treated with actinomycin D shortly before X-irradiation. This treatment abolished the radiation-induced enrichment of polyribosomes and the increase of protein-synthesizing activity. The effect of X-irradiation on the transcription of the genetic code of the liver is discussed.

摘要

对饥饿22 - 24小时的豚鼠进行全身X射线照射，在照射后24小时内研究肝脏RNA的合成。2. 用[¹⁴C]乳清酸在体内对微粒体RNA进行3小时标记，分离得到的标记RNA通过蔗糖密度梯度离心进行分级分离。在2000伦琴X射线照射后3至12小时内，掺入率高出50 - 100%，在22小时时不再进一步升高。用[¹⁴C]乳清酸对全核RNA进行15分钟标记。照射后5小时，掺入率增加了50 - 100%。在所研究的所有类型RNA中，掺入率均增加。3. 肝脏的RNA磷/DNA磷比值在X射线照射后逐渐升高。在24至36小时之间发现最大增幅，该值比饥饿对照高出约40%。从肝脏的各种细胞组分中获得的分离核糖核蛋白的RNA磷含量在X射线照射后也同样增加。4. 从接受X射线照射的动物和对照动物中获取肝脏微粒体。微粒体在有和没有多聚尿苷酸存在的情况下，与[¹⁴C]苯丙氨酸在体外进行孵育。孵育后，通过蔗糖密度梯度离心对微粒体进行分级分离。对照制剂微粒体中的多聚尿苷酸增强作用是照射后微粒体中的两倍。该实验表明，X射线照射后内源性信使对微粒体的饱和度更高。5. 对纯化的细胞核制剂的RNA聚合酶活性进行测定。在X射线照射后6小时和9小时，Mg(²⁺)依赖性RNA聚合酶活性分别比对照值高出50%和200%。6. 在X射线照射前不久，用放线菌素D对动物进行处理。这种处理消除了辐射诱导的多核糖体富集和蛋白质合成活性的增加。讨论了X射线照射对肝脏遗传密码转录的影响。