Abstract
Uroguanylin (UGN) and guanylin (GN) are the endogenous intestinal ligands for guanylyl cyclase C (GC-C). We examined the circadian expression of UGN, GN, and GC-C in the jejunum, ileum, and proximal colon of young adult rats by Northern blot analyses. These assays revealed that UGN is more abundant in the proximal small intestine, whereas GN and GC-C are more abundant in the proximal colon. mRNA levels showed significant circadian variation for UGN (3- to 18-fold peak/trough difference), GN (2.1- to 2.8-fold peak/trough difference), and GC-C (3- to 5-fold peak/trough difference). The maximal abundance occurred in the dark period for all three mRNAs, although peak UGN and GN expression occurred later in the dark period in the jejunum relative to the ileum and colon. Immunoblot analyses using monospecific polyclonal antibodies against UGN and GN prohormones confirmed the regional and circadian variation detected by Northern assays. Thus the expression of these genes is regulated not only by histological position but also by circadian time.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
