25Dihydroxyvitamin

25-Dihydroxyvitamin D, also known as calcitriol, is the active form of vitamin D. It is a secosteroid hormone that plays a crucial role in regulating calcium and phosphate metabolism in the body. The compound is synthesized in the liver and kidneys from vitamin D (cholecalciferol) through the action of enzymes.

The primary function of 25-hydroxyvitamin D is to facilitate the intestinal absorption of calcium and phosphate, which are essential for maintaining proper bone health. The hormone also regulates the expression of genes involved in calcium and phosphate homeostasis, including those involved in bone mineralization, parathyroid hormone production, and osteoclast differentiation.

The name 25-dihydroxyvitamin D refers to the fact that the vitamin D molecule undergoes two consecutive hydroxylation reactions, one in the liver and one in the kidneys, to produce the active form of the vitamin. The compound is essential for regulating calcium and phosphate balance in the body, as well as maintaining healthy bone mineral density.

25-Hydroxyvitamin D deficiency has been linked to various health conditions, including rickets in children and osteomalacia in adults. Treatment of such conditions typically involves supplemental doses of vitamin D, which can be either in the form of cholecalciferol or ergocalciferol. The active form of the vitamin can also be administered directly as calcitriol, especially in cases of severe deficiency or certain medical conditions.

Overall, 25-hydroxyvitamin D plays a vital role in maintaining calcium homeostasis and is an essential nutrient for bone health.