A method for studying plasma transport of vitamin D applicable to hypervitaminosis D

In man, vitamin D is normally transported on a specific binding globulin (DBP) and on lipoproteins. In addition, binding to albumin occurs in the presence of vitamin D excess. Agarose gel electrohoresis was used to study the binding of radioactive vitamin D to plasma proteins in lipoprotein-free plasma (d greater than 1.21 g/ml). This method completely separates DBP from albumin and thus enables the quantification of vitamin D bound to these proteins in various clinical and experimental conditions. The same method can be used to study the transport of other vitamin D metabolites.