Abstract: | The effect of methallibure (ICI 33828) on spermatogenesis was studied in the gerbil, hedgehog, and mouse. Injection of ICI 33828, at a dose of 100 mg/kg for 10-25 days, caused testicular lesions in the gerbil and hedgehog, and spermatogonia were absent in the seminiferous e pithelium. Distinct hypertrophy of the Leydig cells was evident. Acces sory sex gland activity was suppressed. It is possible that ICI 33828 impairs testicular androgen production and luteinizing hormone (LH) activity, as suggested by reduced seminal veisicle weight and reduced concentrations of DNA and RNA. Levels of follicle stimulating hormone and LH were considerably reduced. Both adult male gerbils and hedgehogs were rendered sterile by ICI 33828 at the dose studied, while mice were relatively unaffected. |