Vitamin D has a esteróidic structure, recent research shows 
that has pro vitamin hormonal stimulus leading to anabolic, regulating the expression of a proportion of the human genome which influences the differentiation of many types of cells in the human body.
Many of the genes influenced by the vitamin (regulation of expression), are involved in the production of testosterone. Some studies have demonstrated a correlation between plasma levels of testosterone and vitamin D, the latter being much higher levels, when there is supplementation of vitamin. It is also interesting to note that high levels of vitamin D lead to a sharp fall of (SHBG- sex hormone binding globulin), globulin gives sex hormone ligação. This globulin (protein), is responsible for the inactivation of the testosterone level of muscle tissue, by binding to it and preventing it from exercising its biochemical effects (physiological) leading to increased muscle mass.
Vitamin D also leads to increased levels of IGF1 ( Insulin – like grow factor), insulin-like growth factor. The IGF1 circulates in the blood stream bound to an IGFBP-3 protein, that stabilizes IGF1, preventing its rapid elimination from the body. Recent studies have shown that vitamin D increases the level of IGFBP-3, thereby increasing the physiological activity of the IGF-1.
Insulin is a polypeptide hormone activity substance widely known to glycemic level. However this hormone plays a key role in muscle growth, through a complex pathway, which ultimately ends up activating the enzyme mTOR pathway, which is responsible for stimulation of muscle protein synthesis, and that leads to a protein accumulation to the level of muscular myofibrils, contributing to muscle growth. A leucine, a branched chain amino acid, stimulates insulin activity to muscle level. Recent studies show that vitamin D enhances the ability of this amino acid to activate the insulin.
Last but not least is the fact that vitamin D3 have an activity of inhibiting the conversion of testosterone to estrogen, reducing expression of the aromatase enzyme, which catalyzes this conversion. This contributes to the physiological effect of preventing gynecomastia own and other counterproductive effects of estrogenization, as for example, water retention of the skin and muscle and less muscle detail, and allows greater amounts of testosterone are available for the growth of muscle mass.
Author > Eduardo Ribeiro, CEO scientist Department | Quality control| Research and Development- Biogal, Biologia de Portugal Lda.
