Vitamin D metabolism and analysis of vitamin D2/D3 and their metabolites by liquid chromatography with tandem mass spectrometry (LC-MS-MS) in multiple species

Citation

Rathmacher JA. 2023. Vitamin D metabolism and analysis of vitamin D2/D3 and their metabolites by liquid chromatography with tandem mass spectrometry (LC-MS-MS) in multiple species. In Brooks M, Fidgett A, Kendrick E, Treiber K Eds. Proceedings of the Fifteenth Conference on Zoo and Wildlife Nutrition, Zoo and Wildlife Nutrition Foundation and AZA Nutrition Advisory Group, Hybrid.

Abstract

Low vitamin D status is associated with musculoskeletal diseases, increased mortality, and a range of other diseases. Vitamin D3 is a vitamin that is generated by UV irradiation of 7-dehydrocholesterol and is present in oil-rich fish such as salmon, mackerel, and herring. Vitamin D2 is obtained from the UV irradiation of the sterol ergosterol and is found naturally in sun-exposed mushrooms. As vitamin D3 circulates through the body, metabolism begins by hydroxylation of the vitamin form into the 25-hydroxyvitamin D3 [25OHD3], which is commonly assessed for vitamin D status. 25OHD3 is further metabolized into the active hormone 1?,25(OH)2D3. The predominant circulating form and best indicator of vitamin D status is total 25OHD, which is the total of 25OHD3 and 25OHD2. Sera or plasma are the standard biological specimens used for measuring the circulating 25OHD concentration. We developed an assay to measure 25OHD3 and 25OHD2 using liquid chromatography-tandem mass spectrometry (LC-MS/MS). LC-MS/MS offers high sample volume throughput, high sensitivity, and robust accurate determination of individual analogs of vitamin D based on molecular weight, with low total CV and low error around mean bias. This methodology can be used to assess vitamin D status in mammals, fish, birds, and reptiles.

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