Department of Endocrinology, Medical Research Institute, Tokyo Medical and Dental University, Japan.
Effects of danazol, an isoxazol derivative of the synthetic steroid 17 alpha-ethinyltestosterone, on activities of thymidylate synthetase and thymidine kinase, which are the DNA-synthesizing enzymes included in de novo and salvage pathways of pyrimidine metabolism, respectively, were investigated in rat prostate. Danazol markedly reduced plasma levels of luteinizing hormone and testosterone, and organ weight, both enzyme activities and bromodeoxyuridine-immunoreactive cells which were regarded as the S-phase cells in prostate. These results indicate that danazol shows a property as a potent antigonadotropin.