Skip to Main content Skip to Navigation
Journal articles

Photoperiod and thyroid hormone regulate expression of l -dopachrome tautomerase ( Dct ), a melanocyte stem-cell marker, in tanycytes of the ovine hypothalamus

Abstract : The pars tuberalis (PT) of the pituitary is central to the control of seasonal breeding. In mammals, the PT translates the photoperiodic message carried by melatonin into an endocrine thyroid-stimulating hormone output, which controls local thyroid hormone (TH) signalling in tanycytes of the neighbouring hypothalamus. In the present study, we identify L-dopachrome tautomerase (Dct) as a novel marker of ovine tanycytes and show that Dct displays marked seasonal variations in expression, with higher levels during spring and summer. This seasonal profile is photoperiod-dependent because an acute exposure to long days induces Dct expression. In addition, we find that TH also modulates Dct expression. DCT functions as an enzyme in the melanin synthesis pathway within skin melanocytes, whereas expression in other tissues is comparatively low. We demonstrate that both Tyr and Tyrp1, which are enzymes that intervene upstream and downstream of Dct in the melanin synthesis pathway, respectively, are expressed at very low levels in the ovine hypothalamus. This suggests that Dct in tanycytes may not be involved in melanin synthesis. We speculate that DCT function is linked to its protective role towards oxidative stress and/or its function in the control of neural progenitor cell proliferation.
Document type :
Journal articles
Complete list of metadata

https://hal.inrae.fr/hal-03159533
Contributor : Didier Lomet <>
Submitted on : Thursday, March 4, 2021 - 3:38:06 PM
Last modification on : Friday, May 21, 2021 - 6:13:33 PM

Identifiers

Collections

Citation

Hugues Dardente, Didier Lomet. Photoperiod and thyroid hormone regulate expression of l -dopachrome tautomerase ( Dct ), a melanocyte stem-cell marker, in tanycytes of the ovine hypothalamus. Journal of Neuroendocrinology, Wiley, 2018, 30 (9), pp.1-10. ⟨10.1111/jne.12640⟩. ⟨hal-03159533⟩

Share

Metrics

Record views

27