What is the mechanism of action of vitamin D?

What is the mechanism of action of vitamin D?

The Vitamin D Receptor and Mechanism of Action The active form of vitamin D binds to intracellular receptors that then function as transcription factors to modulate gene expression. Like the receptors for other steroid hormones and thyroid hormones, the vitamin D receptor has hormone-binding and DNA-binding domains.

What receptors does vitamin D bind to?

The vitamin D receptor (VDR also known as the calcitriol receptor) is a member of the nuclear receptor family of transcription factors. Calcitriol (the active form of vitamin D, 1,25-(OH)2vitamin D3) binds to VDR, which then forms a heterodimer with the retinoid-X receptor.

How do you activate vitamin D receptors?

Natural Ways to Increase Calcitrol and Vitamin D Receptor Gene Expression

1. Exercise (R)- increases calcitriol, but not aerobic exercise (R).
2. RXR (and retinol) is needed to produce proteins with the VDR (R).
3. Parathyroid hormone (PTH) – increases Calcitriol/1,25 D3 (R) and PTH -related peptide (R),

What is the mechanism of action of calcitriol?

Calcitriol acts on cells in the gastrointestinal tract to increase the production of calcium transport proteins, termed calbindin-D proteins, which results in increased uptake of calcium from the gut into the body. This is the only mechanism by which the body can increase its calcium stores.

How is vitamin D converted to active form?

The first hydroxylation, which occurs in the liver, converts vitamin D to 25-hydroxyvitamin D [25(OH)D], also known as “calcidiol.” The second hydroxylation occurs primarily in the kidney and forms the physiologically active 1,25-dihydroxyvitamin D [1,25(OH)2D], also known as “calcitriol” [1].

How does vitamin D regulate gene expression?

Studies demonstrate that cholecalciferol can regulate gene expression by direct binding to VDR and that its affinity for VDR is several times higher than the active form of vitamin D (1,25-OH vitamin D) when bound to the vitamin D binding protein44,45.

Is vitamin D receptor a transcription factor?

The vitamin D receptor (VDR) is a nuclear, ligand-dependent transcription factor that in complex with hormonally active vitamin D, 1,25(OH)2D3, regulates the expression of more than 900 genes involved in a wide array of physiological functions.

What does vitamin D receptor activation mean?

Decreased vitamin D receptor (VDR) activation is a major pathophysiologic factor in the development of secondary hyperparathyroidism (SHPT) and contributes to CKD morbidity and mortality. In contrast, VDR inactivation influences bone and cardiovascular disease (CVD) progression and mortality.

What is the role of vitamin D in calcium absorption?

The principal function of vitamin D in calcium homeostasis is to increase calcium absorption from the intestine. Calcium is absorbed by both an active transcellular pathway, which is energy dependent, and by a passive paracellular pathway through tight junctions.

Does vitamin D affect DNA transcription?

The actions of the vitamin D hormone 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) are mediated by the vitamin D receptor (VDR), a ligand-activated transcription factor that functions to control gene expression. These studies are transforming our understanding of how 1,25(OH)2D3 regulates gene transcription.

How does vitamin D work in the skeletal system?

Getting enough vitamin D helps the body absorb calcium which is a bone building mineral. In addition to that task, it also promotes good muscle health. Stronger muscles can work much more effectively in protecting the muscles and supporting the skeletal system. This can help with joint health as well.

What is the role of vitamin D in bone development quizlet?

What is the role of vitamin D in bone development? Vitamin D increases calcium absorption from the small intestine which is used to build bone matrix. Throughout life, bone tissue continues to change.