Endocrine Abstracts

The vitamin D endocrine system (D-endo) is essential for calcium and bone homeostasis. The vitamin D receptor, VDR, is ubiquitously expressed and about 3% of the mouse or human genome is regulated by D-endo. VDR knock-out mice show impaired striated muscle maturation and selective VDR deficiency in heart muscle cause cardiomyopathy. Muscle weakness may be severe in patients with severe chronic renal failure combined with vitamin D deficiency or in subjects with congenital CYP2...

The calcium-sensing receptor (CaSR) plays a central role in regulating parathyroid hormone (PTH) secretion in response to changes in extracellular calcium. The CaSR is a G-protein-coupled receptor and ligand binding results in stimulation of phospholipase C (PLC) activity, causing accumulation of inositol 1,4,5-triphosphate (IP3) and the rapid release of calcium ions from intracellular stores. Given the pivotal role of the CaSR in calcium homeostasis, we decided to ...

Background: Total 25 hydroxyvitamin D (25(OH)D) and total 1.25 dihydroxyvitamin D (1.25(OH)2D) are associated with all-cause mortality. The free hormone hypothesis postulates that only the free vitamin D fraction can exert its biological function. Recently some studies suggested that free 25(OH)D levels might be a better predictor for clinical outcomes, including mortality.Objective: To study the association between total and free 25(OH)D and ...

1,25-Dihydroxyvitamin D3 (1,25(OH)2D3) influences the differentiation and cytokine secretion of various immune cell types. These immune modulating effects of 1,25(OH)2D3 are mediated through the nuclear vitamin D receptor (VDR). In the immune system, the 1,25(OH)2D3/VDR complex interacts with promoter vitamin D responsive elements (VDRE), or interferes with the signalling of other transcription factor...