ABSTRACT
Vitamin D, its metabolites, and analogs constitute a valuable group of compounds that can be used to regulate gene expression in many cells of the body in functions such as calcium and phosphate homeostasis, as well as cell growth regulation and cell differentiation of a variety of cell types (such as enterocytes, keratinocytes, and epithelial lining cells of vascular, GI, and other ductwork of the body) [1,2]. The parent vitamin (or ultraviolet (UV) light that substitutes for any vitamin D pharmaceutical preparation as a source of the parent vitamin) has been used as a treatment for rickets and osteomalacia since its discovery in the 1920s [3]. The discovery of the principal metabolites,
3.1 Introduction ............................................................................................................................65 3.2 Pharmacologically Relevant Vitamin D Compounds .............................................................66
