The induction of reciprocal translocations in mouse germ cells by chemicals and ionizing radiations. II. Combined effects of mitomycin C or thio-tepa with two doses of gamma-rays.
The combined effects of mitomycin C (MMC) and thio-tepa (TT) with gamma-ray doses of 5 and 9 Gy on mouse stem cells were studied using the spermatocyte test. Both chemicals induced very low yields of translocations after single treatments. In combined treatments with a dose of 5 Gy, a subadditive effect of MMC and an additive effect of TT were found. Combined with a dose of 9 Gy the compounds potentiated the effect of radiations. Up to now, most of the chemicals tested have shown additive effects when combined with doses of the ascending part of the dose-response curve and potentiating effects when combined with doses of its descending part. This has been considered additional confirmation of the concept that depletion of any kind of spermatogonia is sufficient to modify the genetic response of stem cells. However, the subadditive and additive responses found could be considered evidence that common biological mechanisms can modulate the response to combined treatments of chemicals and ionizing radiations.
De Luca
J C
JC
IMBICE, La Plata, Argentina.
Dulout
F N
FN
Ulrich
M A
MA
Furnus
C C
CC
Andrieu
J M
JM
D000818:Animals; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D005720:Gamma Rays; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D016685:Mitomycin; D008937:Mitomycins / Q000633:toxicity*; D011839:Radiation, Ionizing; D013093:Spermatogonia / Q000187:drug effects / Q000528:radiation effects; D013094:Spermatozoa / Q000187:drug effects / Q000528:radiation effects; D013852:Thiotepa / Q000633:toxicity*; D014178:Translocation, Genetic / Q000187:drug effects / Q000528:radiation effects
D008937:Mitomycins; D016685:Mitomycin; D013852:Thiotepa