O termo vitamina D engloba a vitamina D produzida na pele (Vitamina D3 ou colecalciferol) e a vitamina D de origem vegetal (Vitamina D2 ou ergocalciferol). O metabólito 1,25 dihidroxicolecalciferol (calcitriol) é a forma ativa da vitamina D, apresentando meia vida de 4 a 6 horas.
What is 1α 25-dihydroxyvitamin D3?
Biologically active form of vitamin D3 in calcium absorption and deposition. 1α,25-Dihydroxyvitamin D3 has widespread effects on cellular differentiation and proliferation, and can modulate immune responsiveness, and central nervous system function.
What is dihydroxyvitamin D?
1,25 dihydroxyvitamin D (1,25 (OH) 2 D) is formed when 25 (OH)D is hydroxylated by the enzyme 1α-hydroxylase (CYP27B1), which is located in the mitochondria of proximal tubules of the kidney. 1,25 (OH) 2 D is the biologically active form of vitamin D.
What is vitamin D1 25 (OH) 2 d?
1,25 (OH) 2 D is a steroidlike hormone. In target cells, such as classic steroid hormones, it binds to a specific cytoplasmic VDR; the vitamin D bound to VDR then translocates to the nucleus, where its effects are initiated at a transcriptional level.
What is the biologically active form of vitamin D?
The biologically active form of vitamin D is 1,25-dihydroxyvitamin D (1,25 (OH) 2 D). Measurement of serum levels of 1,25 (OH) 2 D should be considered upon suspicion of deficiency or excess of this form of the vitamin.