Dual signal transduction pathways activated by TSH receptors in rat primary tanycyte cultures

Bolborea, Matei; Helfer, Gisela; Ebling, Francis J.P.; Barrett, Perry

Abstract

Tanycytes play multiple roles in hypothalamic functions, including sensing peripheral nutrients and metabolic hormones, regulating neurosecretion and mediating seasonal cycles of reproduction and metabolic physiology. This last function reflects the expression of TSH receptors in tanycytes, which detect photoperiod-regulated changes in TSH secretion from the neighbouring pars tuberalis. The present overall aim was to determine the signal transduction pathway by which TSH signals in tanycytes. Expression of the TSH receptor in tanycytes of 10-day-old Sprague Dawley rats was observed by in situ hybridisation. Primary ependymal cell cultures prepared from 10-day-old rats were found by immunohistochemistry to express vimentin but not GFAP and by PCR to express mRNA for Dio2, Gpr50, Darpp-32 and Tsh receptors that are characteristic of tanycytes. Treatment of primary tanycyte/ependymal cultures with TSH (100?IU/l) increased cAMP as assessed by ELISA and induced a cAMP-independent increase in the phosphorylation of ERK1/2 as assessed by western blot analysis. Furthermore, TSH (100?IU/l) stimulated a 2.17-fold increase in Dio2 mRNA expression. We conclude that TSH signal transduction in cultured tanycytes signals via G?s to increase cAMP and via an alternative G protein to increase phosphorylation of ERK1/2.

Citation

Bolborea, M., Helfer, G., Ebling, F. J., & Barrett, P. (2015). Dual signal transduction pathways activated by TSH receptors in rat primary tanycyte cultures. Journal of Molecular Endocrinology, 54, https://doi.org/10.1530/JME-14-0298

• Journal Article Type: Article
• Online Publication Date: Apr 15, 2015
• Publication Date: Jun 1, 2015
• Deposit Date: Jun 23, 2016
• Publicly Available Date: Jun 23, 2016
• Journal: Journal of Molecular Endocrinology
• Print ISSN: 0952-5041
• Electronic ISSN: 1479-6813
• Publisher: BioScientifica
• Peer Reviewed: Peer Reviewed
• Volume: 54
• DOI: https://doi.org/10.1530/JME-14-0298
• Keywords: Thyrotrophin, Pars tuberalis, Median eminence, Neuroendocrine
• Public URL: https://nottingham-repository.worktribe.com/output/750381
• Publisher URL: http://jme.endocrinology-journals.org/content/54/3/241
• Additional Information: Disclaimer: this is not the definitive version of record of this article. This manuscript has been accepted for publication in Journal of Molecular Endocrinology, but the version presented here has not yet been copy-edited, formatted or proofed. Consequently, Bioscientifica accepts no responsibility for any errors or omissions it may contain. The definitive version is now freely available at 10.1530/JME-14-0298 2015.