ALTERED GENE EXPRESSION IN THE FOETAL RAT TESTIS FOLLOWING THE OESTROGEN EXPOSURE

*Gregor Majdic, ^#Philippa TK Saunders *Faculty of veterinary medicine, Gerbiceva 60, 1000 Ljubljana, Slovenia ^#MRC - Reproductive Biology Unit, 37 Chalmers street, Edinburgh EH3 9EW, Scotland

Several reports in recent years have shown evidence for increasing incidence of male reproductive problems as cryptorchidism, hypospadias and testicular cancer. In addition, several reports have published evidence for decrease in sperm counts in many western countries, which might be as high as 50% in the last 50 years. One hypothesis have linked this problems to increased exposure to oestrogenic chemicals during foetal development. Aim of our studies was to establish whether environmental oestrogens could affect testicular development in rats. Time-mated pregnant rats were treated subcutaneously with either diethylstilbestrol (DES, potent synthetic oestrogen), octylphenol (OP, environmental oestrogen) or oil alone as control on days 11.5 and 15.5 p.c. Animals were sacrificed on day 17.5 p.c. Testes were dissected from their foetuses and either fixed in Bouin’s solution, used for RNA extraction or used directly for measuring P450c17 enzyme activity. Lower activity and expression of steroidogenic enzyme P450c17 has been detected in the testes from foetuses whose mothers received either DES or OP. In addition, reduced expression of recently discovered transcription factor Steroidogenic factor-1 (SF-1) has been detected.