title: Synergism between caffeine and gamma-radiation in the induction of dominant lethal mutations in oocytes and spermatozoa of Musca domestica.
abstract: Caffeine was studied with regard to its synergism with gamma-radiation in the induction of dominant lethal mutations in S14 oocytes and mature spermatozoa of M. domestica. In S14 oocytes an increase in the frequency of such a type of mutation was observed only when the exposure to gamma-radiation followed a pretreatment with a diet containing 0.2% of caffeine. Negative results were obtained with (a) post-treatment with the same kind of diet, (b) pretreatment with diets containing 0.1 and 0.02% of caffeine and (c) exposure to the radiation 6 h after interruption of the feeding treatment with the diet containing 0.2% of caffeine. Such influence of the conditions under which the treatment is performed and the synergistic effects is probably related to the food intake pattern and the rapid metabolism of the caffeine. When the 0.2% caffeine pretreatment was combined with an exposure of the oocytes to variable doses of gamma-radiation, the increments in the mutations observed seemed to be negatively correlated to the radiation doses used. Also, under such conditions, the dose/survival relationship fits well an exponential curve expressed by 1n y = -0.866x. With mature spermatozoa, synergism by caffeine was found only when the females, after having been mated with the irradiated males, were fed for 24 h on a diet supplemented with 0.2% of caffeine.
mesh_terms: D000818:Animals; D002110:Caffeine / Q000494:pharmacology*; D005260:Female; D005804:Genes, Lethal; D006793:Houseflies / Q000235:genetics; D008297:Male; D009154:Mutation; D009865:Oocytes / Q000187:drug effects / Q000528:radiation effects*; D010063:Ovum / Q000528:radiation effects*; D013094:Spermatozoa / Q000187:drug effects / Q000528:radiation effects*
chemical_list: D002110:Caffeine