MATERNAL OESTROGEN XENOESTROGEN EXPOSURE ALTERS EXPRESSION OF STEROIDOGENIC FACTOR-I (SF-1/AD4BP) IN THE FETAL-RAT TESTIS/

Expression of steroidogenic factor 1 (SF-1/Ad4BP) is essential for gon adal differentiation. We have assessed whether expression of SF-1 in t he gonads of rat fetuses was altered following maternal treatment with diethylstilbestrol (DES, a synthetic oestrogen) or 4-octylphenol (OP, a xenoestrogen). Pregnant rats were injected subcutaneously with DES (500 mu g/kg), OP (600 mg/kg) or vehicle (oil, control) on days 11.5 a nd 15.5 post coitum (p.c.) and fetal rat testes were recovered on day 17.5 p.c. The level of expression of SF-1 was determined by RNase prot ection assay and immunocytochemistry. In both DES- and OP-exposed fetu ses immunoexpression of SF-1 was reduced in Sertoli and interstitial c ells when compared with controls. In parallel, a significant decrease occurred in the total amount of SF-1 mRNA (P < 0.05) in fetal testes b ut not in fetal ovaries. These results suggest that: (a) Sertoli cell- derived oestradiol may be important in the physiological regulation of SF-1 in the fetal testis; and (b) one mechanism by which inappropriat e exposure to oestrogens might alter the genetic cascade that ensures normal development of the testis is via altered expression of SF-1. (C ) 1997 Elsevier Science Ireland Ltd.