Anti-Estrogen

Estrogen Receptor Antagonists and Aromatase Inhibitors
Antiestrogens can have a variety of effects on pituitary hormone secretion, depending on the ambient hormonal milieu. In premenopausal women and adult men, drugs such as clomiphene, tamoxifen and raloxifene act as estrogen antagonists and block the negative feedback effects of estrogen on gonadotropin secretion, resulting in increased serum LH and FSH. In contrast, opposite effects are seen in postmenopausal women, where the weak estrogen-agonist activity of these compounds predominates, resulting in partial suppression of gonadotropin secretion. Aromatase inhibitors such as letrozole and anastrazole also increase serum gonadotropins in males.