It also activates colonic trace amine-associated receptor 1 in enterochromaffin cells through phenethylamine and tryptamine production—implicated in the pathophysiology of irritable bowel syndrome (IBS)27—and induces Paneth cell antimicrobial responses (Reg3g, Reg3b, and lysozyme-1) via MyD88-dependent signaling.85 Here, REG3G is linked to irritable bowel syndrome.