title: Mechanisms of hormonal regulation of the peripheral circadian clock in the colon.
abstract: Colonic function is controlled by an endogenous clock that allows the colon to optimize its function on the daytime basis. For the first time, this study provided evidence that the clock is synchronized by rhythmic hormonal signals. In rat colon, adrenalectomy decreased and repeated applications of dexamethasone selectively rescued circadian rhythm in the expression of the clock gene Per1. Dexamethasone entrained the colonic clock in explants from mPer2Lucmice in vitro. In contrast, pinealectomy had no effect on the rat colonic clock, and repeated melatonin injections were not able to rescue the clock in animals maintained in constant light. Additionally, melatonin did not entrain the clock in colonic explants from mPer2Lucmice in vitro. However, melatonin affected rhythmic regulation of Nr1d1 gene expression in vivo. The findings provide novel insight into possible beneficial effects of glucocorticoids in the treatment of digestive tract-related diseases, greatly exceeding their anti-inflammatory action.
authors.affiliation: a Department of Neurohumoral Regulations.
authors.forename: Lenka
authors.initials: L
authors.lastname: Polidarová
authors.affiliation: a Department of Neurohumoral Regulations.
authors.forename: Pavel
authors.initials: P
authors.lastname: Houdek
authors.affiliation: a Department of Neurohumoral Regulations.
authors.forename: Martin
authors.initials: M
authors.lastname: Sládek
authors.affiliation: a Department of Neurohumoral Regulations.
authors.forename: Zuzana
authors.initials: Z
authors.lastname: Novosadová
authors.affiliation: b Department of Epithelial Function, Institute of Physiology , The Czech Academy of Sciences , Videnska , Prague , Czech Republic.
authors.forename: Jiří
authors.initials: J
authors.lastname: Pácha
authors.affiliation: a Department of Neurohumoral Regulations.
authors.forename: Alena
authors.initials: A
authors.lastname: Sumová
mesh_terms: D000311:Adrenal Glands / Q000601:surgery; D000818:Animals; D057906:Circadian Clocks / Q000502:physiology*; D003106:Colon / Q000502:physiology*; D005786:Gene Expression Regulation / Q000502:physiology; D051379:Mice; D008815:Mice, Inbred Strains; D009154:Mutation; D056950:Period Circadian Proteins / Q000235:genetics / Q000378:metabolism; D017440:Photoperiod; D010870:Pineal Gland / Q000601:surgery; D051381:Rats; D017208:Rats, Wistar
chemical_list: C513312:Per2 protein, mouse; D056950:Period Circadian Proteins
keywords: Circadian clock; colon; entrainment