Oxymetholone: I. Evaluation in a Comprehensive Battery of Genetic Toxicology and In Vitro Transformation Assays:

Oxymetholone is generally assumed to be a nongenotoxic carcinogen. This assumption is based primarily on the results of an Ames test, existing data in repeat-dose toxicology studies, and the predicted results of a 2-yr National Toxicology Program (NTP) rat carcinogenicity bioassay. To provide a comprehensive assessment of its genotoxicity in a standard battery of mutagenicity assays, oxymetholone was tested in microbial and mammalian cell gene mutation assays, in an in vitro cytogenetics assay (human lymphocytes), and in an in vivo micronucleus assay. Oxymetholone was also tested in an in vitro morphologic transformation model using Syrian hamster embryo (SHE) cells. These studies were initiated and completed prior to the disclosure of the results of the NTP bioassay. Oxymetholone was tested at doses up to 5,000 μg/plate in the bacterial plate incorporation assay using 4 Salmonella strains and the WP2 uvrA (pKM101) strain of Escherichia coli. There was no induction of revertants up to the highest dose lev...