EFFECTS OF IN-UTERO EXPOSURE TO NONSTEROIDAL ESTROGENS ON MOUSE TESTIS

Male mice exposed in utero to alpha-zearalanol (zeranol) or diethylsti lbestrol (DES) were analyzed postnatally to evaluate the possible chan ges on their testicular morphology as part of an examination of the ef fects of transplacental exposure to non-steroidal estrogens on sensiti ve tissues, pregnant NMRI mice were injected subcutaneously with ethyl oleate (0.1 mt) alone (negative control) or with 150 mu g/kg of body weight of zeranol or DES (positive control) on days 9 and 10 of gestat ion, Experimental and control male offspring were euthanized at days 4 5 (n = 47), 90 (n = 44), 180 (n = 40) and 365 (n = 26) after birth and their gonads were examined by light and electron microscopy. The resu lts suggested that prenatal zeranol car DES exposure induced more seve re and earlier (at 45 d) testicular abnormalities than in negative con trol (at 6 mo). These age-related alterations were characterized by re gressive changes ire the germinal epithelium and Sertoli's cells as we ll as foci of Leydig's cells around atrophied seminiferous tubules and dysplasia of the rete testis epithelium, On the contrary, the presenc e of Leydig's cells with immature morphology and their arrangement in sheet could be attributable exclusively to estrogen treatment, The pre sence of no neoplasm was confirmed.