DNA repair processes in germ cells demonstrated in ejaculated sperms of rabbits treated with methyl methane sulfonate
✍ Scribed by B. Schmid; I. P. Lee; G. Zbinden
- Book ID
- 104736222
- Publisher
- Springer-Verlag
- Year
- 1978
- Tongue
- English
- Weight
- 432 KB
- Volume
- 40
- Category
- Article
- ISSN
- 0340-5761
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✦ Synopsis
Male rabbits were treated with a single i.v. injection of 22.5 mg/kg methyl methane sulfonate (MMS). 0--24 h later [3H]-thymidine was injected in both testicles. Incorporation of the isotope in germ cell DNA was demonstrated in ejaculated sperms. In controls labeled sperms were demonstrated first on day 40--43. These cells were in the preleptotene spermatocyte phase at the time of [3H]-thmidine injection. In rabbits treated with MMS significant radioactivity occurred in sperms collected from day 19 onwards. These cells were in late spermatocyte and early spermatid phase of maturation when [3H]-thymidine was injected. Incorporation of thymidine in these cell populations is interpreted as an expression of unscheduled DNA synthesis, a repair process initiated after chemical damage of germ cell DNA by MMS. The usefulness of the rabbit test system within the framework of conventional mutagenicity screening tests is discussed.