Menu > Letrozole
Letrozole is a nonsteroidal competitive inhibitor of aromatase. Aromatase, the enzyme that provides the conversion of androgens (synthesized in the adrenal glands) to estrone and estradiol in women in postmenopause. Given that in some cases the growth of tumor tissues depends on the presence of estrogen, which in postmenopause are formed primarily only with the involvement of aromatase, aromatase inhibitors can reduce the level of estrogen and to create the conditions for the response of the tumor to therapy.
In animal experiments, the use of letrozole resulted in a decrease in weight of the uterus and regression of tumors (hormone dependent) with the efficiency similar to ovariectomy. On the background of therapy with letrozole (unlike ovariectomy) there has been no increase serum levels of follicle-stimulating hormone.
Letrozole selectively inhibits the production of steroids in the gonads, without affecting the production of corticosteroids and mineralokortikosteroidov in the adrenal glands.
The mechanism of oppression aromatase is implemented through competitive binding of letrozole with the heme of cytochrome P450, resulting in reduced estradiol biosynthesis in all tissues of the body.
On the background of therapy with letrozole there is a decrease in the serum levels of estradiol, estrone and estrone sulfate, with no significant effect on the synthesis of aldosterone and corticosteroids, and thyroid hormones.