Vitamin D3 (1.25 OH 2)
General information:
Vitamin D undergoes photolytic conversion in the skin to the parent vitamin D3 (cholecalciferol) after exposure to sunlight. This compound is biologically inactive but enters the circulation and is hydroxylated in the liver to the active 25-OH vitamin D. A small portion of it is hydroxylated in the kidney to the highly active form 1.25 OH Vitamin D. It is bound to the Vitamin D binding protein and albumin in the circulation.
Vitamin D3 is the main regulator of calcium levels in the blood.
Promotes absorption of calcium from the gastrointestinal tract, increases renal tubular reabsorption of calcium, reduces urinary loss, stimulates the release of calcium from bones.
Its levels depend on parathyroid hormone and calcitonin.
The values of the active form of vitamin D are necessary:
- treatment of hypocalcemia in hypoparathyroidism, osteomalacia, CKD
- treatment of osteoporosis
- prevention of corticosteroid-induced osteoporosis
- hypovitaminoses (reduced exposure in countries with little sunshine, vegetarians, problems with food intake)
Sample required:
Venous blood in morning in fasting
Key words:
Vitamin D3