Biomaterial Database

Vitamin D-enhanced duodenal calcium transport. 2015

Kannikar Wongdee, and Narattaphol Charoenphandhu

Office of Academic Management, Faculty of Allied Health Sciences, Burapha University, Chonburi, Thailand; Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand.

For humans and rodents, duodenum is a very important site of calcium absorption since it is exposed to ionized calcium released from dietary complexes by gastric acid. Calcium traverses the duodenal epithelium via both transcellular and paracellular pathways in a vitamin D-dependent manner. After binding to the nuclear vitamin D receptor, 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] upregulates the expression of several calcium transporter genes, e.g., TRPV5/6, calbindin-D9k, plasma membrane Ca(2+)-ATPase1b, and NCX1, thereby enhancing the transcellular calcium transport. This action has been reported to be under the regulation of parathyroid-kidney-intestinal and bone-kidney-intestinal axes, in which the plasma calcium and fibroblast growth factor-23 act as negative feedback regulators, respectively. 1,25(OH)2D3 also modulates the expression of tight junction-related genes and convective water flow, presumably to increase the paracellular calcium permeability and solvent drag-induced calcium transport. However, vitamin D-independent calcium absorption does exist and plays an important role in calcium homeostasis under certain conditions, particularly in neonatal period, pregnancy, and lactation as well as in naturally vitamin D-impoverished subterranean mammals.

UI	MeSH Term	Description	Entries
D007408	Intestinal Absorption	Uptake of substances through the lining of the INTESTINES.	Absorption, Intestinal
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D004386	Duodenum	The shortest and widest portion of the SMALL INTESTINE adjacent to the PYLORUS of the STOMACH. It is named for having the length equal to about the width of 12 fingers.	Duodenums
D006706	Homeostasis	The processes whereby the internal environment of an organism tends to remain balanced and stable.	Autoregulation
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001692	Biological Transport	The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.	Transport, Biological,Biologic Transport,Transport, Biologic
D014807	Vitamin D	A vitamin that includes both CHOLECALCIFEROLS and ERGOCALCIFEROLS, which have the common effect of preventing or curing RICKETS in animals. It can also be viewed as a hormone since it can be formed in SKIN by action of ULTRAVIOLET RAYS upon the precursors, 7-dehydrocholesterol and ERGOSTEROL, and acts on VITAMIN D RECEPTORS to regulate CALCIUM in opposition to PARATHYROID HORMONE.
D018167	Receptors, Calcitriol	Proteins, usually found in the cytoplasm, that specifically bind calcitriol, migrate to the nucleus, and regulate transcription of specific segments of DNA with the participation of D receptor interacting proteins (called DRIP). Vitamin D is converted in the liver and kidney to calcitriol and ultimately acts through these receptors.	Calcitriol Receptors,Cholecalciferol Receptors,Receptors, Vitamin D,Vitamin D 3 Receptors,Vitamin D Receptors,1,25-Dihydroxycholecalciferol Receptor,1,25-Dihydroxycholecalciferol Receptors,1,25-Dihydroxyvitamin D 3 Receptor,1,25-Dihydroxyvitamin D3 Receptor,1,25-Dihydroxyvitamin D3 Receptors,Calcitriol Receptor,Receptors, 1,25-Dihydroxyvitamin D 3,Receptors, Cholecalciferol,Receptors, Vitamin D 3,Receptors, Vitamin D3,Vitamin D 3 Receptor,Vitamin D Receptor,Vitamin D3 Receptor,Vitamin D3 Receptors,1,25 Dihydroxycholecalciferol Receptor,1,25 Dihydroxycholecalciferol Receptors,1,25 Dihydroxyvitamin D 3 Receptor,1,25 Dihydroxyvitamin D3 Receptor,1,25 Dihydroxyvitamin D3 Receptors,D Receptor, Vitamin,D Receptors, Vitamin,D3 Receptor, 1,25-Dihydroxyvitamin,D3 Receptor, Vitamin,D3 Receptors, 1,25-Dihydroxyvitamin,D3 Receptors, Vitamin,Receptor, 1,25-Dihydroxycholecalciferol,Receptor, 1,25-Dihydroxyvitamin D3,Receptor, Calcitriol,Receptor, Vitamin D,Receptor, Vitamin D3,Receptors, 1,25-Dihydroxycholecalciferol,Receptors, 1,25-Dihydroxyvitamin D3