- Activated ergosterol, the vitamin D of plant origin; it arises from ultraviolet irradiation of ergosterol, which is cleaved at the 9,10 bond and develops a double bond between C-10 and C-19; used in prophylaxis and treatment of vitamin D deficiency. SYN: calciferol, ercalciol, viosterol, vitamin D2.
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* * *n.
* * *er·go·cal·cif·er·ol (ur″go-kal-sifґər-ol) [USP] a sterol occurring naturally in fungi and some fish oils or synthesized from ergosterol; it is administered orally or added to food (e.g., milk) as a dietary source of vitamin D. It is also used in the treatment of hypocalcemia, hypophosphatemia, rickets, and osteodystrophy associated with a variety of disorders, such as chronic renal failure and hypoparathyroidism; administered orally, intravenously, or intramuscularly. The activity and metabolism of ergocalciferol are similar to those of cholecalciferol (q.v.). Called also vitamin D2>.
Medical dictionary. 2011.