Endocrine Abstracts

The vitamin D endocrine system (D-endo) is essential for calcium and bone homeostasis. Absence of a functional VDR or CYP27B1 creates a severe rachitic bone and growth plate phenotype in humans and mice as in severe vitamin D deficiency. The intestine is the key target for VDR as a high calcium intake or selective VDR rescue in the intestine restores a normal bone and growth plate phenotype. Selective absence of VDR in osteoblasts does not create a bone phenotype when calcium ...

Ligand activated VDR regulates about 3% the mouse genome. Its classical function is to regulate calcium and bone homeostasis. 1,25-(OH)2D is essential for transepithelial calcium transport in the intestine (by an epithelial calcium channel, TRPV6) and in the kidney (TRPV5). Normal osteoclastogenesis and bone resorption as well as bone mineralisation is possible in the absence of VDR when VDR KO men or animals receive a high calcium diet. VDR.1α,25-(OH)2</s...

Vitamin D is a substrate for the active hormone, 1α, 25-dihydroxyvitamin D3, which binds to a single vitamin D receptor (VDR) belonging to the class of nuclear transcription factors.Ligand activated VDR regulates about 3 % the mouse/human genome and has a wide variety of physiologic actions. Its regulates calcium and bone homeostasis by increasing transepithelial calcium transport (intestine, kidney) and regulates the functions of bone an...