VITINTRA

Vitamin D₂ (ergocalciferol) is a fat soluble vitamin. In conjunction with parathyroid hormone and calcitonin, it regulates calcium haemostasis. Ergocalciferol metabolites promote active absorption of calcium and phosphorous by the small intestine, increase rate of excretion and resorption of minerals in bone and promote resorption of minerals in bone and promote resorption of phosphate by renal tubules.

The presence of vitamin K (i.e. vitamin K or substances with vitamin K activity) is essential for the formation within the body of prothrombin, factor VII, factor IX and factor X. Lack of vitamin K leads to an increased tendency to haemorrhage. When an antidote to an anticoagulant is necessary it is essential to use vitamin K₁ itself, as vitamin K analogues are much less effective.

Vitamin A plays an important role in the visual process. It is isomerised to the 11-cis isomer and subsequently bound to the opsin to form the photoreceptor for vision under subdued light. Vitamin A also participates in the formation and maintenance of the integrity of epithelial tissues and mucous membranes.

Vitamin E is known to exert an important physiological function as an antioxidant for fats, with a sparing action on vitamin A, carotenoids and on unsaturated fatty acids. Other work has demonstrated that vitamin E is connected with the maintenance of certain factors essential for the normal metabolic cycle.