MUTAGENICITY TESTS OF THE ANTITHYROID AGENT THIAMAZOLE. : CYTOGENETIC STUDIES ON MALE MICE

Abstract

The mutagenic potential of thiamazole, an antithyroid agent, was investigated by an in vivo cytogenetic test and was compared with those of mitomycin C and vincristin. These drugs were subcutaneously injected into slc-ICR male mice either as a single dose or as multiple doses for 5 successive days. Thiamazole (90 or 180 mg/kg) did not increase the number of micronuclei in bone marrow cells. This drug also did not induce chromosomal aberrations in spermatogonium, spermatocyte, or bone marrow cells. On the other hand, mitomycin C (3.0 mg/kg) increased the appearance of chromosomal aberrations and micronuclei. Vincristin (0.2 mg/kg) induced bone marrow cells with a so called large micronucleus (d≥D/4). These results suggest that thiamazole may not have significant effects on the genetic systems of mice.