The history of Nolvadex refers to the beginning of 1963, when Arthur Walpole synthesized molecule contraceptive agents and, quite unexpectedly, revealed him more opportunities. Biochemical basis of drug is a derivative triphenylmethylium reinforced hydroxylated metabolite.
Nolvadex (Tamoxifen Citrate 20mg): Description, Application, Side Effects. The history and appearance in clinical practice of the first anti-estrogenic drugs.
Preclinical studies Nolvadex (tamoxifen citrate) were carried out from 1963 to 1968, and in 1969 began a triumphal procession of the drug. Unfortunately, the author did not live to a worldwide recognition of the importance of the opening of Svoge.
- One tablet of Nolvadex contains tamoxifen citrate- 10, 20, 30 or 40 mg.
Action: anti-tumor, anti-estrogen. Competitive blocking estrogen receptors in the target organs and thus inhibits tumor growth, stimulated by estrogen.
- With breast cancer- 20-40 mg per day (1 or 2 applications per day)
- If we sum obtained over the years, data on the mechanism of action of tamoxifen, they can be divided into two groups. The first is its anti-estrogenic effect, which is based on a competitive blocking estrogen receptors (ER) and allows you to get the effect of 50% -70% of patients with positive ER, representing approximately 30% of all breast cancer cases. It should be noted that the determination of this receptor in tumors have become since the mid ’60s, and it served as the basis for understanding the situations in which one part of the patients respond to endocrine therapy, and the other is not.  It is in fact the presence of estrogen receptor in the tumor and a theory predicting response to endocrine therapy of breast cancer cells. It has been observed that the presence of estrogen receptors in patients increases their susceptibility to any hormone therapy. Patients who do not have estrogen receptor in the tumor, the chance of success is 1:10.
- The second group includes the effect of Nolvadex to growth factors such as transforming growth factor – alpha, transforming growth factor – beta, insulin-like growth factor – 1 (IGF-1), and the ability of the drug to reduce the metastatic potential of the tumor by slowing the development of blood vessels and accelerate apoptosis.
- Nolvadex competitively inhibits the binding of estradiol (E2) with a receptor (R) of estradiol.
- Nolvadex causes increased secretion inhibiting growth factor – beta in vitro.
- Nolvadex inhibits secretion of stimulating growth factor – alpha.
- Nolvadex increases the activity of lymphocytes (natural killer cells).
- Nolvadex increases the levels of protein, sex hormone binding (BSPG).
Let us consider in detail each of the above mechanisms. Nolvadex alter normal cellular response to the presence of estradiol by competing with the hormone for binding to the ER. As a result of complex formation estradiol receptor does not occur, and, naturally, the cell does not receive a signal to divide.
- Factors affecting the growth of cells that have entered the cell division cycle. For their transition from the G0 to the next phase of the cell cycle requires the presence of the following factors: the platelet-derived growth factor and fibroblast growth factor. Promotion of competent cells through G1-phase (the duration of which is limited by the rate of cell proliferation) is influenced by factors progression: insulin and epidermal, and transforming growth factors. Therefore, development of cells occurs at a synergistic effect of growth factors in a specific sequence and combination.
It is assumed that the effect on Nolvadex cells develop under the influence of growth factors occurs via the estrogen receptors.
In a recent study, it was demonstrated a similar effect in the ER-negative cells. In vivo provided evidence of a new mechanism of action of Nolvadex . It was found that in cultures of fetal fibroblasts lacking regulatory mechanism mediated by estrogen receptors in response to the presence Nolvadex 30 times increases production inhibitory growth factor – beta. These data demonstrate the ability to act as Nolvadex receptor-positive and receptor-negative cells.
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