Sotomayor R E, Chauhan P S, Ehling U H
Toxicology. 1982;25(2-3):201-11. doi: 10.1016/0300-483x(82)90030-0.
The induction of unscheduled DNA synthesis (UDS) in early spermatid stages of mice was studied after treatment with hydrazine or procarbazine (Natulan). The UDS response was assayed by measuring the levels of [3H]dThd in the nuclei of sperm cells derived from treated and untreated early spermatid stages. The radioactivity present in these nuclei was measured by liquid scintillation counting. Mice were also treated with 100 mg/kg of MMS in order to compare the UDS level induced by this chemical with that induced by hydrazine or procarbazine. The level of UDS induced by hydrazine was not significantly different from that of the untreated controls in any of the 5 doses tested (10-120 mg/kg). Procarbazine, on the contrary, induced UDS in all the 5 doses tested, from 50 to 600 mg/kg. The increase in the UDS response was positively correlated with the increasing dose. The present results with hydrazine indicate either that this compound does not reach the germ cells in sufficient amounts to produce DNA damage or that the repair system in early spermatid stages does not recognize the type of DNA damage produced by this compound. The sensitivity of detection of UDS in the germ cells of male mice is compared with that of the rabbit. At equivalent germ-cell stages and dosage the mouse UDS assay is more sensitive, by a factor of 2 to 3, than the rabbit assay for the induction of UDS by procarbazine and MMS.
在用肼或丙卡巴肼（纳治兰）处理后，研究了小鼠早期精子细胞阶段非程序性DNA合成（UDS）的诱导情况。通过测量来自经处理和未经处理的早期精子细胞阶段的精子细胞核中[³H]胸苷（[³H]dThd）的水平来检测UDS反应。这些细胞核中的放射性通过液体闪烁计数法进行测量。还对小鼠给予100mg/kg的甲基磺酸甲酯（MMS）处理，以便将这种化学物质诱导的UDS水平与肼或丙卡巴肼诱导的UDS水平进行比较。在测试的5个剂量（10 - 120mg/kg）中的任何一个剂量下，肼诱导的UDS水平与未处理的对照组相比均无显著差异。相反，丙卡巴肼在测试的所有5个剂量（50至600mg/kg）下均诱导了UDS。UDS反应的增加与剂量增加呈正相关。目前关于肼的结果表明，要么这种化合物没有足够量到达生殖细胞以产生DNA损伤，要么早期精子细胞阶段的修复系统不能识别这种化合物产生的DNA损伤类型。将雄性小鼠生殖细胞中UDS检测的灵敏度与兔子的进行了比较。在同等生殖细胞阶段和剂量下，小鼠UDS检测对于丙卡巴肼和MMS诱导UDS的灵敏度比兔子检测高2至3倍。
