Lin W, MacKenzie J W, McCoy J R, Clark I
Cancer Biochem Biophys. 1983 Dec;7(1):61-8.
This study describes effects of aflatoxin B1-induced hepatomas on RNA metabolism in rats. At 4 and 24 hours after the administration of L-(14CH3)-methionine, tRNA was isolated from the livers and hydrolyzed enzymatically to nucleosides which were quantitatively measured by HPLC. Radioactivity of the nucleosides was also determined. The data indicate that although tRNA methylation may be more rapid in livers with hepatomas, catabolism of tRNA in tumorous tissue is slower than in control livers. The large increase in some radioactive methylated nucleosides and bases by the tumor-bearing rats during the 24-hour period following the administration of labeled methionine indicates increased turnover of mRNA and rRNA as well as tRNA. Since degradation of tumor tRNA appears to be delayed, the excessive amounts of the urinary methylated nucleosides must be derived from RNA in nonneoplastic tissue.
本研究描述了黄曲霉毒素B1诱导的肝癌对大鼠RNA代谢的影响。在给予L-(14CH3)-甲硫氨酸后4小时和24小时，从肝脏中分离出tRNA并酶解为核苷，通过高效液相色谱法定量测定。还测定了核苷的放射性。数据表明，虽然肝癌肝脏中tRNA甲基化可能更快，但肿瘤组织中tRNA的分解代谢比对照肝脏慢。在给予标记甲硫氨酸后的24小时内，荷瘤大鼠体内一些放射性甲基化核苷和碱基大幅增加，表明mRNA、rRNA以及tRNA的周转率增加。由于肿瘤tRNA的降解似乎延迟，尿中甲基化核苷的过量必定来自非肿瘤组织中的RNA。
