Biological response of the rat epididymis to estrogen

The possible physiological role of estrogen in the epididymis and ventral prostate of rat was investigated. In prepubertal rats castrated for 7 days, treatment with estradiol (1.0 micrograms) for 7 days (35-day-old at autopsy) resulted in a marked increase in the weight and content of glyceryl-phosphorylcholine and sialic acid in the epididymis; estradiol and dihydrotestosterone were equipotent in causing an increase in sialic acid concentration. Estradiol showed a synergistic effect in influencing the androgen action on the growth of the prepubertal rat prostate while no such synergism was evident in stimulating the secretory function of the epididymis. The duality of epididymal response to the two sex steroids suggests that the two hormones may be acting in concert at physiological levels as regulators of epididymal secretory function; the need for identifying estrogen specific biochemical indices in the epididymis is discussed.