This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Grommen, S. V. H. Articles by De Groef, B. Search for Related Content PubMed PubMed Citation Articles by Grommen, S. V. H. Articles by De Groef, B.

Molecular Cloning, Tissue Distribution, and Ontogenic Thyroidal Expression of the Chicken Thyrotropin Receptor

Laboratories of Comparative Endocrinology (S.V.H.G., V.M.D., B.D.G.) and Developmental Physiology, Genomics, and Proteomics (T.J., L.S.), Katholieke Universiteit Leuven, B3000 Leuven, Belgium; and Department of Biology (S.Tan., S.Taka., S.Take.) Faculty of Science, Okayama University, Okayama 700-8530, Japan

Address all correspondence and requests for reprints to: Sylvia Grommen, Laboratory of Comparative Endocrinology, Naamsestraat 61, B-3000 Leuven, Belgium. E-mail: sylvia.grommen{at}bio.kuleuven.be.

TSH and the interaction with its receptor (TSHR) in the thyroid gland play a crucial role in the pituitary-thyroid axis of all vertebrates. Released upon stimulation by TSH, thyroid hormones influence numerous processes in the body and are extremely important during the last week of chicken embryonic development. In this study, we have cloned and functionally characterized the chicken TSHR (cTSHR), which was found to be a G protein-coupled receptor consisting of 10 exons. Besides the full-length cDNA, we detected two splice variants lacking either exon 3, or exons 2 and 3, both part of the extracellular domain of the receptor. Bovine TSH increased intracellular cAMP levels in HEK-239 cells transiently expressing the full-length cTSHR (EC₅₀ = 1.43 nM). In situ hybridization showed the expression of cTSHR mRNA in the thyroidal follicular cells. cTSHR mRNA expression, as determined by real-time PCR, was also found in several other tissues such as brain, pituitary, pineal gland, and retina, suggesting that the TSH-TSHR interaction is not only important in regulating thyroid function. TSHR mRNA expression in the thyroid gland did not change significantly during the last week of embryonic development, which suggests that an increased thyroidal sensitivity is not part of the cause of the concomitant increasing T₄ levels.