What is the action of tamoxifen?
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What is the action of tamoxifen?
Tamoxifen is a type of hormonal therapy known as a selective estrogen receptor modulator (SERM). The drug attaches to hormone receptors (specific proteins) in breast cancer cells. Once the medication is inside the cells, it stops the cancer from accessing the hormones they need to multiply and grow.
How does tamoxifen act What is the primary target of the drug?
Tamoxifen competitively inhibits estrogen binding to its receptor, which is critical for it’s activity in breast cancer cells. Tamoxifen leads to a decrease in tumor growth factor α and insulin-like growth factor 1, and an increase in sex hormone binding globulin.
What is indication of tamoxifen?
Indications. Tamoxifen is indicated for the treatment of breast cancer in a variety of settings. It should be noted that evidence suggests that patients with estrogen receptor-positive tumors are more likely to benefit from tamoxifen. [1] Tamoxifen also has many off-labeled uses, and they may require additional data.
What effect does tamoxifen have on the body?
Tamoxifen blocks the effects of estrogen on hormone receptor-positive breast cancer cells by sitting in the estrogen receptors on the cells. If tamoxifen is in the receptor, estrogen can’t attach to the cancer cell and the cell doesn’t receive estrogen’s signals to grow and multiply.
Is tamoxifen an agonist or antagonist?
Tamoxifen is both an antagonist and an agonist of the estrogen receptor. However, a molecular explanation exists for this apparent paradox. The dual action is a function of the estrogen receptor complex present in a particular cell or tissue.
How does tamoxifen block the action of oestrogen?
Tamoxifen works by blocking the oestrogen receptors. It stops oestrogen from telling the cancer cells to grow. Tamoxifen belongs to a group of drugs called selective oestrogen receptor modulators or SERMs.
Is tamoxifen an estrogen blocker?
For example, tamoxifen blocks the effects of estrogen in breast tissue but acts like estrogen in the uterus and bone. Other antiestrogen drugs, such as fulvestrant (Faslodex), work in a somewhat different way to block estrogen’s effects.
Is tamoxifen an estrogen antagonist?
Tamoxifen is both an antagonist and an agonist of the estrogen receptor.
What class of drug is tamoxifen?
Tamoxifen is in a class of medications known as antiestrogens. It blocks the activity of estrogen (a female hormone) in the breast. This may stop the growth of some breast tumors that need estrogen to grow.
Is tamoxifen a hormone blocker?
Is flutamide an agonist?
In contrast, the nonsteroidal antiandrogens such as flutamide are generally considered pure antiandrogens that do not exhibit AR agonist activity (23, 27). Yet both steroidal and nonsteroidal antiandrogens can sometimes lack antagonist actions and/or act as partial AR agonists in nonneuronal cells (24, 28, 29).
How is tamoxifen an agonist?
In breast tissue, tamoxifen acts as an ER antagonist so that transcription of estrogen-responsive genes is inhibited. A beneficial side effect of tamoxifen is that it prevents bone loss by acting as an ER agonist (i.e., mimicking the effects of estrogen) in this cell type.
What drug class is tamoxifen?
Tamoxifen is in a class of medications known as antiestrogens. It blocks the activity of estrogen (a female hormone) in the breast.
Does tamoxifen reduce estrogen?
What does estrogen hormone do?
In females, it helps develop and maintain both the reproductive system and female characteristics, such as breasts and pubic hair. Estrogen contributes to cognitive health , bone health, the function of the cardiovascular system , and other essential bodily processes.
Why is tamoxifen an agonist?
If a cell type requires activating factors 1 and 2 of the estrogen receptor to be functioning concurrently, tamoxifen is antagonistic. However, if a cell or tissue requires only activating factor 1 to interact with transcription factors at the promoter, tamoxifen is agonistic.
What is androgen receptor antagonist?
A substance that keeps androgens (male sex hormones) from binding to proteins called androgen receptors, which are found in normal prostate cells, some prostate cancer cells, and in cells of some other tissues. Preventing this binding blocks the effects of these hormones in the body.
How is tamoxifen an agonist and antagonist?
