Richardson K K, Rexroat M A, Helvering L M, Copple D M, Richardson F C
Toxicology Research Laboratories, Eli Lilly and Company, Greenfield, IN 46140.
Carcinogenesis. 1992 Jul;13(7):1277-9. doi: 10.1093/carcin/13.7.1277.
Hepatocellular tumors were induced in 15 day old male B6C3F1 mice following a single exposure to N-nitrosodiethylamine (DEN; 5 mg/kg, i.p.). Tumors were collected at 38 and 65 weeks to compare the frequencies and types of mutations in the 61st codon of the H-ras oncogene. The 61st codon was amplified using the polymerase chain reaction (PCR). Allele-specific oligonucleotide (ASO) probes were used to determine the frequency and types of mutations present in these tumors. Forty-nine nodular hepatic lesions were obtained from seven animals at the 38 week timepoint. Five of these samples (10%) had mutations at the 61st codon with one CAA-AAA, one CAA-CGA and three CAA-CTA. Thirty-six nodular hepatic lesions were obtained from six animals at the 65 week timepoint. Ten of these samples (28%) had mutations at the 61st codon with one CAA-AAA, five CAA-CGA and four CAA-CTA. These data indicate that DEN-induced mutations at the 61st codon of the mouse H-ras oncogene (i) are an infrequent event, (ii) have different frequencies at the 38 and 65 week timepoints and (iii) are different from the types of mutations seen in spontaneous lesions.
给15日龄雄性B6C3F1小鼠单次腹腔注射N-亚硝基二乙胺（DEN；5毫克/千克）后诱发肝细胞肿瘤。在38周和65周时收集肿瘤，以比较H-ras癌基因第61密码子处的突变频率和类型。使用聚合酶链反应（PCR）扩增第61密码子。等位基因特异性寡核苷酸（ASO）探针用于确定这些肿瘤中存在的突变频率和类型。在38周时间点从7只动物身上获得了49个结节性肝损伤。其中5个样本（10%）在第61密码子处发生突变，分别为1个CAA-AAA、1个CAA-CGA和3个CAA-CTA。在65周时间点从6只动物身上获得了36个结节性肝损伤。其中10个样本（28%）在第61密码子处发生突变，分别为1个CAA-AAA、5个CAA-CGA和4个CAA-CTA。这些数据表明，DEN诱导的小鼠H-ras癌基因第61密码子处的突变：（i）是罕见事件；（ii）在38周和65周时间点有不同的频率；（iii）与自发损伤中所见的突变类型不同。
