25-hydroxy-Vitamin D total (rat) ELISA

Immunoenzymetric assay for the quantitative measurement of 25-hydroxyvitamin D2 and D3 (25OH-D2 and 25OH-D3) in rat serum. Vitamin D is the generic term used to designate Vitamin D2 or ergocalciferol and Vitamin D3 or cholecalciferol. In the liver mainly, Vitamin D3 is metabolised into 25-Hydroxyvitamin D3 (25OH D3) which is the main form of Vitamin D circulating in the body. 25OH D3 is a precursor for other Vitamin D metabolites and has also a limited activity by itself. The most active derivative is 1,25-hydroxyvitamin D3, produced in the kidney (or placenta) by 1-hydroxylation of 25OH D3. 25OH Vitamin D stimulates the intestinal absorption of both calcium and phosphorus and also bone resorption and mineralisation. Rats have been used as experimental model to investigate the effect of 25OH Vitamin D supplements on fracture healing. 25OH Vitamin D might also be active in other tissues responsible for calcium transport (placenta, kidney, mammary gland …) and endocrine gland (parathyroid glands, beta cells…). Vitamin D3 and Vitamin D2 are also available by ingestion through food or dietary supplementation. As Vitamin D2 is metabolised in a similar way to Vitamin D3, both contribute to the overall Vitamin D status of an individual. Studies on rats have been conducted to compare metabolism of oral Vitamin D2 and oral Vitamin D3.(6) and to define the effect of Vitamin D3 intake on calcium metabolism. Influence of vitamin D deficiency during intra uterine and early life on blood pressure has been suited in a rat model. In studies on rat PTH (parathyroid hormone), 25OH vitamin D is measured in rat serum to determine its influence on PTH secretion.