Dietary calcium absorption

Dietary calcium absorption is a physiological process in which calcium from ingested food is absorbed through the intestine into the bloodstream. This is achieved via two major mechanisms: - Transcellular active transport, occurring predominantly in the duodenum and upper jejunum, involving: - Entry through the apical calcium channel TRPV6 (also called CaT1 or ECaC) - Intracellular transport by calbindin D9k (CaBP) - Extrusion via the plasma membrane calcium ATPase (PMCA1b) and Na+/Ca2+ exchanger (NCX1) - This route is tightly regulated by the active vitamin D metabolite (1,25(OH)2D3) acting on the vitamin D receptor (VDR) - Paracellular passive diffusion, which occurs throughout the intestine and is facilitated by tight junction proteins, especially claudins (notably claudin-2, claudin-12, and claudin-15), and is driven primarily by concentration gradients[1][3][5][7][8]. The process is not a receptor or single molecule, but includes components that are valid drug/vitamin targets and may serve as drug or research targets (most notably, TRPV6, VDR, and possibly claudin family proteins). For structured target information, individual components such as "TRPV6 (transient receptor potential cation channel subfamily V member 6)", “Vitamin D receptor (VDR)", or "Plasma membrane calcium-transporting ATPase 1 (PMCA1b)" should be used. "Dietary calcium absorption" itself does not map cleanly to a canonical molecular target. Key molecular participants: - TRPV6: channel mediating apical entry of calcium[3][6][7] - Vitamin D receptor (VDR): nuclear receptor controlling gene expression of absorption machinery[3][6][7] - Calbindin D9k (CaBP): intracellular calcium-binding protein[1][7] - PMCA1b: ATPase pumping calcium out of enterocyte[8] - Na+/Ca2+ exchanger (NCX1): alternative calcium efflux[8] - Claudins (claudin-2, claudin-12, claudin-15): form tight junctions for paracellular calcium movement[5] References for main mechanisms: - [1] [3] [5] [6] [7] [8] In summary, "Dietary calcium absorption" is not a molecular target, but a composite physiological process involving several defined targets, most notably TRPV6, VDR, and claudins.

Other names

intestinal calcium absorptiongut calcium absorptionintestinal Ca2+ absorptioncalcium uptake (intestinal)