Abstract
In order to eliminate changes of pituitary hormone secretion secondary to treatment and be able to assess the direct effect of 17β-estradiol and prolactin at the level of hormone-dependent mammary tumors induced in the rat by 7,12-dimethylbenz(a)anthracene (DMBA), the effects of the two hormones on steroid receptor levels were investigated in hypophysectomized-ovariectomized animals. Treatment with prolactin alone led to tumor estrogen receptor levels higher than those found after estrogen administration. When the level of progesterone receptors was measured as parameter of estrogen action, it was found that combined treatment with prolactin and 17β-estradiol led to levels much higher than those found after individual hormone treatment. Tissue specificity of this interaction between prolactin and 17β-estradiol is indicated by the absence of effect of prolactin on the estrogen-induced stimulation of the progesterone receptor in uterine tissue. These data demonstrate the direct stimulatory effect of prolactin on estrogen receptor levels in DMBA-induced mammary carcinoma and indicate the central role of this pituitary hormone as modulator of estrogen action and growth of DMBA-induced mammary tumors.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call