VDR and Hypocalcemia: Further, 1,25(OH)2D3 regulates calcium and phosphorus homeostasis in mineral-regulating organs, such as the intestine, bone, kidney, and parathyroid glands by binding to vitamin D receptor (VDR) [3], and has been widely used to treat hypocalcemia, metabolic bone diseases, hypoparathyroidism, and cancer [2,4].