Intestinal fluid secretion and water retention in the gut lumen

Intestinal fluid secretion and water retention in the gut lumen refer to the physiological mechanisms governing the movement of water and electrolytes across the intestinal epithelium (Barrett & Keely, 2015). This balance is maintained by a complex interplay of ion channels, transporters, and pumps, such as the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) and Sodium-Hydrogen Exchanger 3 (NHE3), which create osmotic gradients (Field, 2003). Dysregulation of these processes leads to clinical conditions like secretory diarrhea, where excessive fluid is secreted, or constipation, where excessive absorption or inadequate secretion occurs (Thiagarajah et al., 2015). Therapeutic strategies often target specific molecular components of this system; for example, guanylate cyclase-C agonists like Linaclotide stimulate fluid secretion to treat constipation, while NHE3 inhibitors like Tenapanor reduce sodium absorption to increase luminal water (Layer et al., 2021). Conversely, drugs like Crofelemer inhibit chloride channels to treat diarrhea by reducing fluid secretion (Bardhan et al., 2009). Understanding these pathways is essential for managing functional gastrointestinal disorders and maintaining systemic fluid homeostasis.

Other names

Intestinal fluid transportGut water homeostasisIntestinal water secretionIntestinal fluid homeostasisLuminal fluid accumulation

Modulation of intestinal ion channels (e.g., CFTR, ClC-2) and transporters (e.g., NHE3) to alter the osmotic gradient and regulate luminal water content (Barrett & Keely, 2015; Layer et al., 2021).