Background: Adaptive cytoprotection could be demonstrated in lesion attenuationwithin the whole gastrointestinal tract, in particular sequences, with onset and duration longer thanthe initial short-lasting period (i.e. one hour) defined by Robert in the stomach only. Material/Methods:Adaptive cytoprotection possibly appeared and lesions were attenuated when the stomach, duodenum or colon,in various combinations and sequences, were challenged with initial (mild) and/or final (strong) irritantsover a two-week period. Rats were challenged with the mild or strong irritants 25% or 96% ethanol intragastrically1 ml/rat (stomach) and cysteamine 40 mg or 400 mg/kg subcutaneously (duodenum), or intrarectally (colon).To postulate the prostaglandin relationship known in Robert's cytoprotection and adaptive cytoprotection,indomethacin (1 mg/kg subcutaneously) was given simultaneously with the second challenge. Results: Administeringthe mild and strong irritant protocols within the same part of the gastrointestinal tract, adaptive cytoprotectionpresents in the stomach (1 h to 14 days), duodenum (2 h to 14 days), but not in the colon. With theseprotocols applied to different parts of the gastrointestinal tract, adaptive cytoprotection cross-reactionwas evident in the stomach-duodenum, duodenum-stomach (1 h-14 days and 2 h-14 days), stomach-colon, andduodenum-colon (both 2-24 hours), but not in the colon-stomach or colon-duodenum. This protection wasfully antagonized with indomethacin. Conclusions: As observed for a day and even weeks, stomach-duodenum-colonadaptive cytoprotection is an important new defensive phenomenon.

Keywords: Adaptation, Physiological, Colon - physiopathology, Cysteamine - toxicity, Duodenum - physiopathology, Ethanol - toxicity, Gastric Mucosa - physiopathology, Intestinal Mucosa - physiopathology, Irritants - toxicity, Necrosis