Fallopian tube epithelial cells of the Mongolian Sheep(Ovis aries) were cultured in the medium containing estradiol.Concentration of estradiol was 10^-11,10^-10,10^-9,10^-8,10^-7,10^-6 or 0 mol/L.After culturing for 24,48,and 72 hours,total RNA was extracted and the cDNA encoding sBD-1 was amplified by RT-PCR,respectively.The results show that sBD-1 expression in Fallopian tube epithelial cells is evidently affected by estradiol treatment.There is a positive correlation between sBD-1 expression and estradiol concentration when the hormone is added less than 10^-8 mol/L,while sBD-1 expression is decreased when estradiol concentration is more than 10^-8 mol/L.The data are very important for understanding the relation between estradiol and the defensin.