Mutagenicity of 2-bromopropane.

2-Bromopropane (2BP, isopropyl bromide), a substitute for freon, has recently been suspected to be the causative chemical for the outbreak of some reproductive dysfunctions such as amenorrhea and oligospermia in workers who has been exposed to this solvent in an electronic factory. Bacterial mutation assays, chromosome aberration analysis in vitro, and micronucleus tests in vivo, were carried out to clarify the mutagenicity of 2BP. 2BP induced mutagenicity in Salmonella typhimurium TA100 with metabolic activation in a dose-dependant manner. 2BP induced mutagenicity in TA1535 as well, with or without metabolic activation. These observations indicated that 2BP induced the base-pair substitution type mutations in Salmonella strains. The chromosome aberration analysis showed negative results in Chinese hamster lung cells treated with different concentrations, ranging from 0.077 to 2.46 mg/ml for 6 h with metabolic activation and for 24 h without metabolic activation. The micronucleus frequencies were recorded by examining polychromatic erythrocytes in the bone marrows of rats which were intraperitoneally injected with 2BP for 28 days. There was no significant increase in the micronucleus frequencies at any of the different doses of 2BP (125 mg/ kg b.w./day, 250 mg/kg b.w./day, and 500 mg/kg b.w./day). However, in comparison to controls, there was a significant decrease in the percentage of polychromatic erythrocytes in the total number of erythrocytes. This suggests that there may be bone marrow depression in hematopoiesis at these dose levels of 2BP. Despite the dose levels which showed hematopoietic inhibition in the bone marrow, no micronucleus formation was induced.