NEONATAL EXPOSURE TO DIETHYLSTILBESTROL PERMANENTLY ALTERS THE BASAL AND 17-BETA-ESTRADIOL INDUCED EXPRESSION OF C-FOS PROTOONCOGENE IN MOUSE URETHROPROSTATIC COMPLEX

Perinatal estrogen exposure induces permanent structural and functiona l changes in the male reproductive tract. We have studied the effect o f neonatal estrogenization on the estrogen-responsive c-fos proto-onco gene expression in mouse prostate. Fos is involved in growth and diffe rentiation, and may play a central role in regulating diverse estrogen -related cellular differentiation. In adult control mouse prostate, ba sal c-fos mRNA expression is very low. Neonatal treatment with diethyl stilbestrol on days 1-3 (neoDES) results in permanently increased fos expression in the prostatic urethra and all prostatic lobes. In adult castrated animals, estradiol induces a rapid transient increase in c-f os expression in the prostatic urethral with maximum induction being h igher in neoDES animals. In situ hybridization and immunohistochemistr y show that in neoDES mice Sos transcripts and protein are localized p rimarily in the epithelium of posterior periurethral prostatic collect ing ducts. These are the sites previously reported to show the most pr onounced morphological changes after estrogen treatment. Our results i ndicate that neonatal estrogenization affects both basal and estrogen stimulated c-fos mRNA levels in the prostate of mature mice, which sup ports the hypothesis that estrogen-induced morphological changes in mo use prostate may involve altered c-fos expression. (C) 1997 Elsevier S cience Ireland Ltd.