Vitamin D or the hormone?

In 1936, A. Khain, and then centuries Khvorov, Century A. Rusakov (1937), and others established the effect of vitamin D on the function of the parathyroid glands. Further studies showed an effect on a number of other endocrine glands (the adrenal, pituitary, and others). In this regard, in the literature there have been reports that vitamin D in the body manifests itself as hormone (antagonist of parathormone). For the first time the mechanism of action of vitamin D was associated with the implementation of hereditary information, containing in the structure of the gene, i.e. the question was raised about hormonal nature of the mechanism of its action (Zull a. oth., 1966).
Opening metabolite 1,25-dihydroxycholecalciferol-roll formed in the kidneys and showing its particular effect on the absorption of calcium in the intestine through the system of DNA - RNA (with education in ribosomes calzievogo protein), clarified in the study of this question. It is known that hormones are active biological substances, acting through the genetic system of cells in very small quantities. In addition, for the hormones it is characteristic that they are produced in some bodies, enter the bloodstream and then specifically apply in other organs, which are physiological targets. Meets all these conditions 1,25-DGHC that has led some authors to include the connection to the steroid hormones that regulates the exchange of calcium in the body (Dambacher, Girarg, 1972; Foradori, 1972). Currently, vitamins of group D can be attributed to a group of steroid hormones, which is confirmed by the following data.
1. The synthesis of vitamin D comes from acetate and cholesterol like the synthesis of steroid hormones.
2. Vitamin D is converted in the body into active metabolites, and steroid hormones.
3. The mechanism of action it is very similar to that of steroid hormones. Vitamin D affects biological membranes and genetic apparatus of cells organs targets regulating synthesis calzievogo protein. The organism appears in the form of kongugatov steroids.
4. As steroid hormones, vitamin D has an effect on the distance from the place of synthesis, has its target organs, receptor molecules. Distributed in the body like a steroid hormone.
5. A lack or excess of vitamin D lead to the shift of the metabolism of other steroids. Thus, vitamin D is synthesized in the body or introduced from outside, undergoes a series of complex transformations. The most intensively absorbed vitamin D2 in the duodenum, and for suction required the presence of bile. Originally vitamin D comes in the lymphatic system, then contacts a chylomicrons and blood lipoproteins. Portal vein enters the liver, where it is associated with the A2-globulin fraction. This connection protects the molecule of vitamin D from the destructive effect of enzymatic systems. In addition, it plays an important role in the transport of vitamin to the receptors of the target organs. In the liver under the influence of 25-hydroxylase in the molecule of vitamin D joins one hydroxyl group with the formation of the 25-hydroxycholecalciferol. The last in the kidneys, where with the participation of the 1-hydroxylase joins the second hydroxyl group with the formation of 1,25-digit-Toxicological. Then a large part of the newly formed metabolite through the blood enters the small intestine (12 duodenal ulcer), where appears the main purpose of vitamin D on the absorption of calcium (Strukov, 1974).
Consequently, it is possible to consider that the mechanism of action of vitamin D is induced them synthesis and RNA with further education in ribosomes calzievogo protein.
Most researchers believe that the nucleus of the cells lining the small intestine concentrate the bulk of metabolites of vitamin D. However, the precise localization of metabolites in the kernel is not fully elucidated. According to some authors, most vitamin D linked directly to the chromatin, according to others with nuclear membrane, containing specific receptors binding of this vitamin. It can be assumed that further study of the intracellular distribution of vitamin D will finally reveal the molecular mechanisms of its action.