MOUSE DOMINANT LETHAL AND SPERM ABNORMALITY STUDIES WITH COMBINED EXPOSURE TO X-RAYS AND MITOMYCIN-C

The induction of dominant lethal effects and sperm abnormalities in Pz h:Swiss male mice after treatments with X-rays and mitomycin C (MMC) w as investigated. Combinations of high (1.00 Gy + 5.25 mg/kg bw MMC) an d low (0.25 Gy + 1.75 mg/kg bw MMC) doses of both agents were used. Ex posure to high doses of X-rays + MMC induced an increased rate of domi nant lethal mutations in spermatogonia and late spermatocytes. Combine d treatment with low doses of X-rays and MMC was not mutagenic in any stage of spermatogenesis. MMC increased the frequency of abnormal sper matozoa after exposure alone and in combination with X-rays. Treatment with two high doses (1.00 Gy + 5.25 mg/kg bw MMC) induced 58.4% abnor mal spermatozoa. After combined exposure to low doses of both agents 3 5.7% spermatozoa with malformations were observed.