Anti Estrogens

Areas of application of this active substance group

Antiestrogens are substances that antagonize the action of the female sex hormone estrogen. Depending on the antiestrogen used, this elimination of action only affects specific aspects of the estrogen effect, while others remain. Thus, the anti-estrogens open up a fairly broad range of fields of application.

Anti-estrogens are used whenever the body’s female sex hormone estrogen has an undesirable effect in the body. These undesirable effects include:

  • Certain forms of breast cancer that are stimulated by estrogen for growth. In addition to the inhibition of tumor growth, anti-estrogens also reduce the spread of cancer cells into the rest of the body. In this way, they reduce the risk of developing secondary tumors (metastasis). Are used here estrogen receptor antagonists such as fulvestrant , tamoxifen and toremifene. Should not be treated with the active substances on the breast, substances from the group of aromatase inhibitors for use. Their effect is not based on the inhibition of estrogen effects, as in the case of anti-estrogens, but on the fact that they prevent the formation of estrogens in the body.
  • Unfulfilled childhood, which is based on a disturbance in the hormonal control circuit between the ovary, the pituitary gland and the brain. This disorder does not cause ovulation, no egg is inserted into the uterine lining. Thus the women have a month’s bleeding, but are still sterile. Here antiestrogens ready clomiphene favor the conception. They cause the secretion of the hormone gonadoliberin in the cerebrum, which triggers ovulation and ovulation via the pituitary gland.
  • Complaints by bone loss ( osteoporosis ) in women after menopause. Here antiestrogens ready raloxifene have a preventive effect or alleviate symptoms.

Antistrogens act like this

All anti-estrogens at least partially increase the effect of estrogens. They are divided into four groups in principle due to their mechanisms of action:

1. estrogen receptor antagonists block the binding sites (receptors) for estrogen to the target organs, such as the cells of the breast tissue. This prevents estrogen-promoted size growth and uncontrolled cell division in breast cancer. In addition, fewer tumor cells can migrate into the surrounding tissue or vessels. The risk for the formation of daughter tumors is clearly reduced. Examples of estrogen receptor antagonists include fulvestrant , tamoxifen and toremifene.

2. Anti-estrogens with partial estrogen effect (partial antagonists) are both similar to the female hormone and slightly estrogen-like. In order to understand their effect in the case of an unfulfilled wish for the child, one must know how the hormonal control system works:

  • To trigger ovulation, the gland has to eject the hormone gonadoliberin.
  • Gonadoliberin causes the production of other hormones, the gonadotropins, in the pituitary gland.
  • The gonadotropins, in turn, are carried with the blood to the ovaries and dissolve the secretion of estrogens and the migration of an ice into the uterus (ovulation).
  • If the estrogen concentration in the blood then rises above a certain value, the estrogen binds to the receptors of the interbrain and the pituitary gland, which stops the production of gonadrotropin and gonadoliberin. In the case of permanently elevated estrogen levels, then no ovulation can take place.

The active ingredient clomifene now binds to the receptor in the brain like estrogen, but does not trigger the effects typical of estrogen. The mechanism of action has still not been clearly clarified, but the active substance of the brain pituitary gland is “predicted” that the body produces too little estrogen. The reaction of the pituitary gland is due to the increased secretion of hormones. They promote the maturation of the eggs in the ovary and ovulation.

3. Selective estrogen receptor modulators (SERMs) such as bazedoxifene , raloxifene and tamoxifen are relatively new anti-estrogenic substances. They have similar effects as estrogens but do not have the side effects on the breast and uterus. They do not induce breasts and do not stimulate the uterine lining. In principle, they should only be administered after the very last month’s bleeding (menopause). The SERMs inhibit estrogen as bone loss and are therefore for the prophylaxis and treatment of osteoporosis admitted.

4. Another large group of anti-estrogens are the aromatase inhibitor . The inhibition of the enzyme aromatase directly limits the production (production) of estrogens. Thus, the same effects are produced as with the other antiestrogens. Aromatase inhibitors are used primarily in breast cancer therapy, if therapy with the other anti-estrogens described here does not or only insufficiently.

All anti-estrogens lead to partial significant side effects due to the artificial estrogen deficiency. There may be heat buildup, chest tension and dryness as well as itching in the vaginal area. It also increases the risk of blood clots or changes in the uterine lining. Regular inspections are therefore required at the doctor’s office.

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