n. 1,25-dihydroxycholecalciferol: the final and most metabolically active form of vitamin D3. It is formed in the kidney by the addition of two hydroxy (?OH) groups to the basic vitamin D molecule, which itself is produced in the skin from 7-dehydrocholesterol or ingested in certain foods. Calcitriol is given to raise blood calcium levels in patients with severe kidney disease and to treat postmenopausal osteoporosis. It is also used as an ointment to treat psoriasis.
Health Encyclopedia