Abstract
Chronic admn. of sulfamethazine to normal young male rats caused gross and microscopic atrophic changes in the testes, seminal vesicles and anterior prostate, but a hyperplasia of the thyroid gland. When hypophysectomized rats were fed with sulfamethazine, only increased atrophy of the testes was manifested. These changes are attributed to a direct effect of the drug on the testes. The hypertrophy of the accessory organs of the young male rats treated with sulfamethazine as reported by Asplin and Boyland was not confirmed.