Vitamin D
Updates to Article Attributes
Vitamin D is used to describe a group of five fat-soluble secosteroids. Vitamin D is a prohormone that exists in two forms in humans (D2 and D3).
Physiology
Vitamin D2 is artificially created by irradiation of ergosterol from yeast or fungi and is used for supplementation and pharmaceutical purposes. Vitamin D3 is the endogenously produced compound resulting from ultraviolet exposure to 7-dehydrocholesterol in the deeper layers of the skin. D2 is artificially created by irradiation of ergosterol from yeast or fungi and is used for supplementation and pharmaceutical purposes.
Both Vitamin D2 and D3 must undergo two sequential hydroxylations at the carbon 25 position in the liver and kidneys to the active hormonal form 1,25-dihydroxyvitamin D3 (1,25[OH]2D3). The 1α hydroxylating enzyme is found exclusively in renal tissue (25-OH-D-1α hydroxylase).
The active hormonal form acts on the intestine and bone for homeostatic maintenance of serum calcium and phosphorus levels and mineralization of bone.
Related pathology
Pathological manifestations can occur both in excess and deficiency:
- hypervitaminosis D
- hypovitaminosis D
- paediatric: rickets
- adult: osteomalacia
See also
- hypophosphatemic vitamin D-refractory rickets and osteomalacia
- vitamin D-dependent rickets (a.k.a. pseudovitamin D-deficiency rickets)
-
citaminvitamin D-resistant rickets- cystinosis
- X-Linked hypophosphatemia
- parathyroid gland abnormalities
- pseudohypoparathyrodism (Albright's hereditary osteodystrophy)
- pseudopseudohypoparathyrodism
-<p><strong>Vitamin D</strong> is used to describe a group of five fat-soluble secosteroids. Vitamin D is a prohormone that exists in two forms in humans (D<sub>2</sub> and D<sub>3</sub>).</p><h4>Physiology</h4><p>Vitamin D<sub>3</sub> is the endogenously produced compound resulting from ultraviolet exposure to 7-dehydrocholesterol in the deeper layers of the skin. D<sub>2</sub> is artificially created by irradiation of ergosterol from yeast or fungi and is used for supplementation and pharmaceutical purposes. </p><p>Both Vitamin D<sub>2</sub> and D<sub>3</sub> must undergo two sequential hydroxylations at the carbon 25 position in the liver and kidneys to the active hormonal form 1,25-dihydroxyvitamin D<sub>3</sub> (1,25[OH]<sub>2</sub>D<sub>3</sub>). The 1α hydroxylating enzyme is found exclusively in renal tissue (25-OH-D-1α hydroxylase).</p><p>The active hormonal form acts on the intestine and bone for homeostatic maintenance of serum calcium and phosphorus levels and mineralization of bone.</p><h4>Related pathology</h4><p>Pathological manifestations can occur both in excess and deficiency:</p><ul>- +<p><strong>Vitamin D</strong> is used to describe a group of five fat-soluble secosteroids. Vitamin D is a prohormone that exists in two forms in humans (D<sub>2</sub> and D<sub>3</sub>).</p><h4>Physiology</h4><p>Vitamin D<sub>2</sub> is artificially created by irradiation of ergosterol from yeast or fungi and is used for supplementation and pharmaceutical purposes. Vitamin D<sub>3</sub> is the endogenously produced compound resulting from ultraviolet exposure to 7-dehydrocholesterol in the deeper layers of the skin. </p><p>Both Vitamin D<sub>2</sub> and D<sub>3</sub> must undergo two sequential hydroxylations at the carbon 25 position in the liver and kidneys to the active hormonal form 1,25-dihydroxyvitamin D<sub>3</sub> (1,25[OH]<sub>2</sub>D<sub>3</sub>). The 1α hydroxylating enzyme is found exclusively in renal tissue (25-OH-D-1α hydroxylase).</p><p>The active hormonal form acts on the intestine and bone for homeostatic maintenance of serum calcium and phosphorus levels and mineralization of bone.</p><h4>Related pathology</h4><p>Pathological manifestations can occur both in excess and deficiency:</p><ul>
-<li>citamin D-resistant rickets<ul>- +<li>vitamin D-resistant rickets<ul>
Unable to process the form. Check for errors and try again.