Expression of urocortin and corticotropin-releasing hormone receptors in the horse thyroid gland.
Urocortin (UCN) is a 40-amino-acid peptide and a member of the corticotropin-releasing hormone (CRH) family, which includes CRH, urotensin I, sauvagine, UCN2 and UCN3. The biological actions of CRH family peptides are mediated via two types of G-protein-coupled receptors, namely CRH type 1 receptor (CRHR1) and CRH type 2 receptor (CRHR2). The biological effects of these peptides are mediated and modulated not only by CRH receptors but also via a highly conserved CRH-binding protein (CRHBP). Our aim was to investigate the expression of UCN, CRHR1, CRHR2 and CRHBP by immunohistochemistry, Western blot and reverse transcription with the polymerase chain reaction (RT-PCR) in the horse thyroid gland. The results showed that UCN, CRHR1 and CRHR2 were expressed in the thyroid gland, whereas CRHBP was not expressed. Specifically, UCN immunoreactivity (-IR) was found in the thyroid follicular cells, CRHR2-IR in the C-cells and CRHR1-IR in blood vessels. Western blot analysis and RT-PCR experiments confirmed the immunohistochemical data. These results suggest that a regulatory system exists in the mammalian thyroid gland based on UCN, CRHR1 and CRHR2 and that UCN plays a role in the regulation of thyroid physiological functions through a paracrine mechanism.
Department of Structure, Functions and Biological Technologies, University of Naples Federico II, Via Veterinaria 1, 80137 Naples, Italy. caterina.squillacioti@unina.it
Caterina
C
Squillacioti
Adriana
A
De Luca
Sabrina
S
Alì
Salvatore
S
Paino
Giovanna
G
Liguori
Nicola
N
Mirabella
D000818:Animals; D015153:Blotting, Western; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation; D006736:Horses / Q000378:metabolism*; D007150:Immunohistochemistry; D047468:Immunoprecipitation; D008297:Male; D018019:Receptors, Corticotropin-Releasing Hormone / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013961:Thyroid Gland / Q000166:cytology / Q000378:metabolism*; D054832:Urocortins / Q000235:genetics / Q000378:metabolism*; D000099052:CRF Receptor, Type 1
C101531:CRF receptor type 2; D002352:Carrier Proteins; D018019:Receptors, Corticotropin-Releasing Hormone; D054832:Urocortins; C067133:corticotropin releasing factor-binding protein; D000099052:CRF Receptor, Type 1