Gastrointestinal secretory processes

Gastrointestinal secretory processes encompass the coordinated release of enzymes, acids, bicarbonate, and fluids across the stomach, small intestine, and colon to facilitate digestion, absorption, and protection of the mucosal lining. These processes are primarily driven by enteroendocrine cells, parietal cells, and epithelial ion transporters, involving key mechanisms like CFTR-mediated Cl⁻ secretion in the intestine, H⁺/K⁺-ATPase-driven acid production in the stomach, and NKCC1-coupled ion uptake. Neural (e.g., acetylcholine via M3 receptors) and hormonal (e.g., VIP, gastrin) signals regulate secretion through cAMP, Ca²⁺, and second messengers, enabling rapid adaptation to nutrient intake. Dysregulation contributes to disorders like secretory diarrhea from toxin-activated CFTR or gastric ulcers from excess acid, and in gastrointestinal cancers, altered secretion ties to cancer stem cell pathways influencing tumor progression. Therapeutically, targets within these processes include proton pump inhibitors for acid suppression and CFTR modulators for diarrhea, though challenges include balancing secretion without disrupting motility or microbiome.

Other names

gastric secretionintestinal secretionGI secretionCl⁻ secretiongastric acid secretion

cAMP elevation via GsPCRs activating CFTR Cl⁻ channels; Ca²⁺ increase via GqPCRs activating KCNN4 K⁺ channels and Cl⁻ efflux; H⁺ secretion inhibition via H⁺/K⁺-ATPase blockade; NKCC1-mediated ion uptake for Cl⁻ secretion