Effects of melatonin, testosterone and the two hormones administered in parallel on epididymis of the rat estrogenized with stilbestrol in the first day of life.

Effect of melatonin, testosterone and of both hormones given in parallel on rat epididymis was tested in rats given a single dose of 1 mg stilbestrol on the first day of the life. The hormones were given daily for 39 days, beginning from the 20th or 28th day of life. The single dose of estrogen treatment resulted in epididymis atrophy, accompanied by changes in glandular epithelium and in its stroma, when the rats reached mature age (59 or 67 days of life). In such rats, LH gonadotropin level was elevated and testosterone level was decreased. Administration of melatonin failed to affect the changes induced by estrogen treatment. Administration of testosterone alone or of testosterone in parallel with melatonin caused the epididymis status to resemble more closely that seen in control animals. Efferent ductules of the testis (head of epididymis) were also demonstrated to be more sensitive to the performed experimental procedures than the duct of the epididymis (body and tail of the epididymis).