Intestine

The intestines are a vital organ system within the gastrointestinal tract, traditionally divided into the small intestine (comprising the duodenum, jejunum, and ileum) and the large intestine (comprising the colon and rectum) [6, 10]. They perform essential biological functions including the enzymatic digestion of food, the absorption of nutrients and electrolytes, and the reabsorption of water to form solid waste [6, 11]. Beyond digestion, the intestines play a critical role in systemic immunity through the gut-associated lymphoid tissue (GALT) and serve as an endocrine organ, secreting hormones such as glucagon-like peptide-1 (GLP-1) and serotonin that regulate metabolism and motility [7, 12]. In the pharmaceutical industry, the intestines are often studied as a site for localized drug delivery to treat conditions like Inflammatory Bowel Disease (IBD) or as a physiological barrier containing transporters (e.g., P-gp, PEPT1) and enzymes (e.g., CYP3A4) that dictate the bioavailability of oral medications [6, 13]. While the term "intestines" refers to an anatomical structure rather than a discrete molecular target, it encompasses numerous specific receptors and pathways—such as Guanylate cyclase-C and the Wnt/beta-catenin signaling pathway—that are targeted to treat gastrointestinal and metabolic disorders [1, 7].

Other names

BowelGutGastrointestinal tract (part)Intestinal tract

Drugs targeting the intestines act via diverse localized mechanisms, including the inhibition of pro-inflammatory cytokines such as TNF-alpha to reduce mucosal inflammation, the activation of luminal receptors like Guanylate cyclase-C to stimulate fluid secretion and intestinal transit, or the modulation of the enteric nervous system through opioid or serotonin receptor pathways [6, 12]. Additionally, some therapies target specific intestinal transporters (e.g., SGLT1 or ASBT) to manage metabolic conditions and bile acid malabsorption [1, 13].