Tamoxifen Catalog Description (30.4mg/ml, 60ml)
Tamoxifen (trade name Nolvadex) is a selective estrogen receptor modulator (SERM) that acts as an estrogen receptor (ER) antagonist in breast tissue; uses of tamoxifen include treatment of breast cancer in women after menopause and treatment of female infertility caused by ovulatory dysfunction. Tamoxifen is sometimes used off-label by clinicians for treatment of drug-induced gynecomastia, as an androgen substitute, and for male infertility. Other documented effects of SERMs such as tamoxifen include increased bone mass and reduced cholesterol, without the negative side-effects of excessive estrogens.
The primary mechanism of action for the main functions of tamoxifen is estrogen receptor (ER) antagonism, wherein tamoxifen or its metabolites bind to the ER with no effect, and displace or prevent binding of estrogen. The actual effects of tamoxifen administration occur locally (as in breast cancer or gynecomastia) as well as downstream (as in hypothalamic-pituitaric mediated effects such as androgen substitute and male infertility). Tamoxifen can raise testosterone in men by lowering bound estradiol and triggering a negative hypothalamic feedback loop; high estrogen levels cause the body to inhibit production of the male hormone testosterone, while tamoxifen reverses this cascade without actually lowering circulating estrogen.
A lesser-known mechanism of action of tamoxifen is ER agonism or partial activation; this mechanism is responsible for the observed increased bone mass, reduced total and low-density lipoprotein (LDL) cholesterol numbers, and vaginal/uterine effects. The partial agonism in some cell types is the reason tamoxifen belongs to the SERM class of compounds.
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