ANTI-HORMONES (grech, anti-against + hormone[s]) — the natural and synthetic substances capable to brake effect of the corresponding hormone. As the structure of hormones is various (steroids, peptides etc.), a structure And. also widely varies though in relation to each specific hormone in group it And. it is possible to allocate the most widespread class of connections always. E.g., among anti-androgens there are more than 200 connections of several various classes, however most of them is steroids (tsiproteron, A-nor-testosteron, A-nor-progesteron etc.).
And. to proteinaceous hormones are usually proteins. One of types And. — so-called anahormones — the derivatives of natural hormones deprived of biological activity as a result of certain chemical modifications.
Specific mechanism of action various And., even in relation to the same hormone, can be unequal. At the same time philosophy of action of many And. it is identical and consists in the following: And., having considerable affinity to a receptor of this hormone in a target cell, contact this receptor and by that block linkng of hormone with it. Since in most cases And. have no biological activity of this hormone or possess it in much smaller degree, that their linkng with a receptor does not lead to development of hormonal effect. And. have high hormonal specificity. So, anti-estrogen (e.g., MER-25, tetrahydrofuran) blocks effect of estrogen in a uterus and does not change action of androgens in the same fabric as receptors of these hormones are various.
Some And., acting by such principle, have a molecule of the corresponding hormone in the basis, but modified in a varying degree. At synthesis of such connections aim to keep affinity to the receptors connecting initial hormone, but in the maximum degree to reduce the corresponding hormonal activity.
The possibility of existence in an organism natural is not excluded And. In particular, at the person and animals it is emitted several substances which are slowing down action of both endogenous, and exogenous gonadotrophins (anti-gonadotrophins). Natural And. can participate in fiziol. the mechanisms regulating effect of hormones.
And. find application in experimental endocrinology, giving the chance to the experimenter to switch off function of hormone, without resorting to surgical removal of the corresponding gland. Are especially convenient, e.g., And. for studying of formation and a role of endocrine system in an embryogenesis. And. can find application and in clinic (blockade of effect of hormones at hormonal dependent tumors, the sexual behavior patholologically changed etc.).
Introduction And. gives the chance to switch off effect of the corresponding hormone regardless of the place of its education whereas during surgical removal of one gland there is always a possibility of secretion of the same hormone other closed glands or educations it in many peripheral fabrics from hormones structurally close to it. As a rule, effect And. completely we will turn that is big advantage at their use.
See also Antimetabolites .
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B. V. Pokrovsky.