Temporary cell cycle arrest in neural and extraneural developing rat tissues after exposure to methyl--and ethylnitrosourea.

摘要: 8 days old rats were exposed to 20 or 100 mg/kg b.w. of either Methylnitrosourea (MNU) Ethylnitrosourea (ENU), followed by injection 10 μCi/g (3H-methyl)-Thymidine. After a mg dose MNU ENU in both neural and extraneural tissues total inhibition S-phase radioactivity is observed that lasts longer for than ENU. Moreover reappearance cells the later (36–48 h) (24–36 drugs. In consistently found occur about 12 h earlier recurrence M-phase cells. clear decrease after 6 h' interval only. There are only slight differences between various developing rat there obviously trend mitotic activity with increasing single doses Our results point an arrest before entering involved. The more pronounced cytotoxic as compared discussed. Recurrence DNA synthesis re-entrance damaged into their cycle prior elimination altered bases from might be importance problem oncogenesis.