The effects of prenatal diethylstilbestrol exposure on the genitalia of pubertal Macaca mulatta. II. Male offspring

In order to evaluate the potential embryotoxic and fetotoxic effects of in utero diethylstilbestrol (DES) exposure on the developing offspring, 19 pregnant rhesus mponkeys were administered 1 mg/day DES orally beginning on either day 19 (group I), 100 (group II) or 130 (group III) of gestation and terminating on the day of natural birth or cesarean section. Five of ten male offspring are alive at 7 years of age. At 4 1/2 years of age, three of these five offspring exhibited one or more abnormalities of the external genitalia, including testicular hypoplasia, preputial adhesions and undescended testes. Semen analysis following rectal electroejaculation and testicular biopsies at 5 1/2 years of age confirmed two cases of testicular biopsies and analysis of serum testosterone levels at 6 1/2 years of age indicated normal testicular morphology and function in all DES-exposed males as compared with colony controls. Our study, therefore, suggests that DES may affect maturation of the reproductive tract as indicated by a delay in the normal breakdown of preputial adhesions in addition to gross and microscopic evidence of testicular hypoplasia during the postpubertal period between 4 1/2 and 5 1/2 years of age. Further observations on breeding performance and fertility are required to evaluate the long-term effects of DES in this species.