title: Effect of X-ray and ethylnitrosourea exposures separated by 24 h on specific-locus mutation frequency in mouse stem-cell spermatogonia.
abstract: Specific-locus mutation frequencies in mouse stem-cell spermatogonia were determined in 3 experiments in which mature male mice were exposed to 100,m 300, or 500 R of X-rays followed, 24 h later, by intraperitoneal injection of 100 mg/kg of ethylnitrosourea (ENU). The purpose was to find out if the mutation frequencies would be augmented over those expected on the basis of additivity of the effects of the separate treatments. Such augmentation had been observed in earlier work in which exposure to 100 or 500 R of X-rays was followed 24 h later by a second exposure of 500 R. No augmentation was observed for X-rays followed by ENU. The mutation frequencies in all 3 experiments actually fell below those expected on the basis of additivity, although the reductions were not statistically significant.
authors.affiliation: Biology Division, Oak Ridge National Laboratory, TN 37831.
authors.forename: W L
authors.initials: WL
authors.lastname: Russell
authors.forename: D A
authors.initials: DA
authors.lastname: Carpenter
authors.forename: S
authors.initials: S
authors.lastname: Hitotsumachi
mesh_terms: D000818:Animals; D005038:Ethylnitrosourea / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D005808:Genes, Recessive / Q000187:drug effects / Q000528:radiation effects; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D013093:Spermatogonia / Q000187:drug effects / Q000528:radiation effects; D013094:Spermatozoa / Q000187:drug effects / Q000528:radiation effects; D014965:X-Rays
chemical_list: D005038:Ethylnitrosourea