CHRONIC ADMINISTRATION OF 4-TERT-OCTYLPHENOL TO ADULT MALE-RATS CAUSES SHRINKAGE OF THE TESTES AND MALE ACCESSORY SEX-ORGANS, DISRUPTS SPERMATOGENESIS, AND INCREASES THE INCIDENCE OF SPERM DEFORMITIES

The environmental toxicant 4-tert-octylphenol (OP) has been shown to e xert estrogenic effects on mammalian cells in culture. Recent findings from our laboratories demonstrate clearly that OF administration disr upts reproductive hormone secretion in the adult male rat, quite likel y as a result of estrogenic action. In the present study, we investiga ted the impact of these or other OF-induced changes on male reproducti ve tissues. Adult male rats were injected with OP (20 or 80 mg) or est radiol valerate (EV; 0.8 or 8 mu g) s.c. in oil three times a week for either 1 or 2 mo. We found that an 80-mg dosage of OP for 2 mo or an 8-mu g dosage of EV for 1 or 2 mo greatly reduced sperm numbers and ad versely influenced the sizes, weights, and histological structures of the testes, epididymides, ventral prostate glands, seminal vesicles, a nd coagulating glands. The 80-mg dosage of OP for 1 mo reduced epididy mal tubule size to a lesser extent than after 2 mo of treatment. Other wise, treatment with 80 mg OP for 1 mo, 20 mg OP for 1 or 2 mo, or 0.8 mu g EV for 1 mo had little or no effect on the histology of the tiss ues we examined. Additional evaluation of sperm morphology revealed ma rked increases in the proportions of head and tail abnormalities from animals that had received 80 mg of OP or 8 mu g of EV for 1 mo and 20 mg of OP far 2 mo. The head abnormalities consisted mainly of pin head s, detached heads, and the absence of hooks, while tail abnormalities included mainly broken, coiled, and bent fails. Our results clearly de monstrate that OP can severely reduce the size and/or function of all of the male gametogenic and accessory reproductive organs studied. Mor eover, the similarity of these cell and tissue changes between rats tr eated with OP and those treated with EV further suggests that OP may e xert its action in an estrogenic-like manner.