Water absorption in the small intestine

Water absorption in the small intestine refers to the net movement of water from the intestinal lumen into the body's circulation, predominantly via osmosis driven by active solute (particularly sodium) absorption. This process depends primarily on the transport of sodium through several mechanisms: nutrient-coupled sodium absorption (via transporters such as SGLT1), electroneutral sodium chloride absorption (mediated by Na+/H+ exchangers like NHE3), and paracellular pathways. Water follows solute absorption down osmotic gradients, generally via transcellular (through cells) and paracellular (between cells) routes. Most water absorption is tightly linked to sodium movement, with sodium export into intercellular spaces creating osmotic gradients. Aquaporins and tight junction proteins also contribute. Impairments in these mechanisms can cause clinical syndromes such as congenital sodium diarrhea or contribute to pathologies such as diarrhea during intestinal inflammation or after transporter inhibition by drugs like tenapanor. Water absorption itself is not a druggable molecular entity, but its underlying mechanisms involve multiple drug targets (e.g., NHE3)[1][2][3][4]. If you are seeking a specific molecular target for drug development or research, such as a channel, receptor, or transporter associated with water absorption in the small intestine, likely candidates would be: - Sodium-glucose co-transporter 1 (SGLT1) - Sodium/hydrogen exchanger 3 (NHE3) - Aquaporins (especially AQP1, AQP3) Please specify one of these or another discrete molecule/receptor if you require structured data on a conventional therapeutic target.

Other names

Water absorptionSmall intestine water transportIntestinal water reabsorption

Inhibition of NHE3 reduces sodium (and thus water) absorption