Influence of steroid hormones on the carcinogenicity of 90Sr

Groups of female CBA-mice were given 90Sr (14.8 kBq/g-0.4muCi/g--bodyweight) alone or in combination with polyestrodiolphosphate, methylprednisolone or nortestosterone, respectively. When 90Sr was given in the first combination, the frequency of osteosarcomas was significantly increased whereas the tumour latency time was decreased compared to mice given 90Sr alone. In combination with nortestosterone such effects were not found, whereas the combination 90Sr + methylprednisolone resulted in a strong reduction of the osteosarcoma incidence and a prolonged tumour latency time. The latter experiment was repeated in a larger experiment whereby the results were confirmed.