title: TR(beta)1 protein is preferentially expressed in the pericentral zone of rat liver and exhibits marked diurnal variation.
abstract: We investigated the distribution and diurnal variation of TR(beta)1 protein expression in liver with specific antibodies against TR(beta)1. Immunohistochemistry showed a zonal distribution of TR(beta)1 with maximum expression in the pericentral zone matching some known T(3)-responsive enzyme activities in the liver, such as glutamine synthetase, cholesterol 7alpha- hydroxylase, and spot 14. Combining immunohistochemistry and image analysis we found and quantified the same zonal distribution for 5'-deiodinase type 1 as for TR(beta)1. Western blot analysis revealed a profound diurnal variation for TR(beta)1 protein expression, with highest levels at the beginning of the dark period. TR(beta)1 diurnal variation partly overlaps with the T(3)-responsive genes, cholesterol 7alpha-hydroxylase and spot 14. Furthermore, TR(beta)1 distribution along the porto-central axis does not change during the day, indicating that the zonal expression of TR(beta)1 is stable. This is the first time that zonal distribution in liver has been demonstrated for a member of the nuclear receptor family. This finding together with the observed diurnal rhythm has major implications for interpreting and timing experiments concerning the TR and its downstream actions in liver.
authors.affiliation: Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands.
authors.forename: Behrouz
authors.initials: B
authors.lastname: Zandieh Doulabi
authors.forename: Marianne
authors.initials: M
authors.lastname: Platvoet-ter Schiphorst
authors.forename: Hermina C
authors.initials: HC
authors.lastname: van Beeren
authors.forename: Wil T
authors.initials: WT
authors.lastname: Labruyere
authors.forename: Wouter H
authors.initials: WH
authors.lastname: Lamers
authors.forename: Eric
authors.initials: E
authors.lastname: Fliers
authors.forename: Onno
authors.initials: O
authors.lastname: Bakker
authors.forename: Wilmar M
authors.initials: WM
authors.lastname: Wiersinga
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002940:Circadian Rhythm / Q000502:physiology*; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics; D005974:Glutamate-Ammonia Ligase / Q000096:biosynthesis / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D007453:Iodide Peroxidase / Q000096:biosynthesis / Q000235:genetics; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D051381:Rats; D011988:Receptors, Thyroid Hormone / Q000096:biosynthesis* / Q000235:genetics; D014162:Transfection; D014284:Triiodothyronine / Q000502:physiology
chemical_list: D011988:Receptors, Thyroid Hormone; D014284:Triiodothyronine; D007453:Iodide Peroxidase; D005974:Glutamate-Ammonia Ligase