Testosterone-induced micronuclei and increased nuclear division rate in L929 cell line expressing the androgen receptor

Data on the possible genotoxic effects of testosterone are limited: in particular, the potential clastogenic and/or aneugenic effects have not yet been properly investigated. An in vitro micronucleus (MN) assay was performed on L929 cells exposed to testosterone at doses of 10, 15, 20, 30, and 40 μg/mL. Significantly increased MN frequencies were detected at doses of 20, 30, and 40 μg/mL after 24 h and 48 h of incubation. The nuclear division index was higher after 48 h than 24 h of incubation. A benchmark dose (BMD) calculation was used to estimate the 1% extra risk level for MN and increased tetranucleated cells. The calculated 1% extra risk level for MN at 24 h was 12.01 μg/mL, with a 95% lower confidence limit (BMDL) at 8.98 μg/mL; the corresponding BMD and BMDL at 48 h were 17.35 μg/mL and 10.69 μg/mL, respectively. The BMD for tetranucleated cells at 24 h was 14.86 μg/mL, with a BMDL of 7.75 μg/mL; the corresponding values at 48 h were 0.50 μg/mL for BMD and 0.87 μg/mL for BMD. These findings suggest that the intensity of the mitogenic effect of testosterone increases upon prolonged exposure. The results of our study show that testosterone acts both as a mitogenic and genotoxic agent in L929 cells.