Involvement of thyrotropin in photoperiodic signal transduction in mice

• DOI: 10.1073/pnas.0808952105
• Publication Date: 2008-11-18T02:40:39Z
• Authors: Hiroko Ono; Yuta Hoshino; Shinobu Yasuo; Miwa Watanabe; Yusuke Nakane; Atsushi Murai; Shizufumi Ebihara; Horst-Werner Korf; Takashi Yoshimura
• Keywords: DIO2; Pars tuberalis; Thyroid-stimulating hormone

Local thyroid hormone catabolism within the mediobasal hypothalamus (MBH) by hormone-activating (DIO2) and -inactivating (DIO3) enzymes regulates seasonal reproduction in birds mammals. Recent functional genomics analysis has shown that long days induce thyroid-stimulating production pars tuberalis (PT) of pituitary gland, which triggers DIO2 expression ependymal cells (EC) MBH. In mammals, nocturnal melatonin secretion provides an endocrine signal photoperiod to PT contains receptors high density, but interface between perceived levels MBH remains unclear. Here we provide evidence mice TSH participates this photoperiodic transduction. Although most mouse strains are considered be nonseasonal, a robust response comprising induced TSHB (TSH beta subunit), CGA alpha DIO2, reduced DIO3, was observed melatonin-proficient CBA/N mice. These responses could not elicited melatonin-deficient C57BL/6J, treatment C57BL/6J with exogenous similar effects on above-mentioned genes as after transfer short-day conditions. The EC found express receptor (TSHR), ICV injection expression. Finally, show administration did affect TSHB, DIO3 TSHR-null Taken together, our findings suggest melatonin-dependent regulation appears involve