[A mutagenicity study of calcipotriol (MC903)]

Calcipotriol (MC903), an anti-psoriasic agent, was examined for mutagenicity in the reverse mutation test and the chromosomal aberration test in vitro, and the micronucleus test in Slc:ddY mice. 1. In the reverse mutation test using Salmonella typhimurium (TA100, TA1535, TA98, TA1537) and Escherichia coli (WP2uvrA), MC903 did not significantly increase revertant colonies in any of the test strains with or without metabolic system. 2. In the chromosomal aberration test with a Chinese hamster fibroblast cell line (CHL), MC903 did not significantly increase aberrant cells in the direct method or in the activation method. 3. In the micronucleus test with male mice, MC903 did not significantly increase in the number of polychromatic erythrocytes with micronuclei in the bone marrow. These results suggest that MC903 has no mutagenic as well as clastogenic effects under the present experimental condition.