Mutagenicity of methyl 2-benzimidazolecarbamate, diethylstilbestrol and estradiol: structural chromosomal aberrations, sister-chromatid exchanges, C-mitoses, polyploidies and micronuclei.

Methyl 2-benzimidazolecarbamate (MBC), diethylstilbestrol (DES) and estradiol were tested with regard to their ability to induce C-mitoses, polyploidies, micronuclei, structural chromosomal aberrations and sister-chromatid exchanges (SCE) in human peripheral lymphocytes in vitro. The compounds did not induce structural chromosomal aberrations either in the presence or absence of metabolic activation. MBC and estradiol were negative in the SCE test. DES induced SCE rates which were not even twice the control level and which were independent of dose and of metabolic activation. All compounds induced C-mitoses, polyploidies and micronuclei. The micronuclei are interpreted as resulting from errors in the anaphase distribution of chromosomes by spindle disturbances rather than from structural chromosomal aberrations.