Dihydroxyvitamin D 3 (1, 25D) is the renal metabolite of vitamin D that signals through
binding to the nuclear vitamin D receptor (VDR). The ligand–receptor complex
transcriptionally regulates genes encoding factors stimulating calcium and phosphate
absorption plus bone remodeling, maintaining a skeleton with reduced risk of age-related
osteoporotic fractures. 1, 25D/VDR signaling exerts feedback control of Ca/PO 4 via
regulation of FGF23, klotho, and CYP24A1 to prevent age-related, ectopic calcification …