title: Biologic clocks and the gut.
abstract: The gastrointestinal tract displays biologic rhythms in basal gastric acid output, epithelial cell proliferation, gastrointestinal motility, and appetite regulation. Furthermore, the development of gastrointestinal complications after administration of aspirin and after chemo- and radiotherapy for metastatic colon cancer depends on the time of administration. Biologic rhythms are driven by so-called clock genes. Thus, it is conceivable that subsets of genes in the gastrointestinal tract are under clock gene control as well. The purpose of this article is to discuss basic concepts in the studies of biologic rhythms, to review examples of biologic rhythms in the gastrointestinal tract, and to discuss examples of gastrointestinal diseases in which alterations in biologic rhythms may play a pathogenetic role.
authors.affiliation: Department of Internal Medicine, Division of Gastroenterology, The University of Michigan, 1500 East Medical Center Drive, 3912 Taubman Center, Ann Arbor, MI 48109-0362, USA.
authors.forename: Willemijntje A
authors.initials: WA
authors.lastname: Hoogerwerf
mesh_terms: D000818:Animals; D001066:Appetite / Q000502:physiology; D001683:Biological Clocks / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology; D004734:Energy Metabolism / Q000502:physiology; D004847:Epithelial Cells / Q000502:physiology; D005744:Gastric Acid / Q000378:metabolism; D005769:Gastrointestinal Motility / Q000502:physiology; D041981:Gastrointestinal Tract / Q000502:physiology*; D006801:Humans; D007413:Intestinal Mucosa / Q000502:physiology; D013270:Stomach / Q000502:physiology