春天一到就知道该求偶繁衍后代的动物，是如何察觉季节更替的呢？日本名古屋大学的研究人员，在２０日出版的英国《自然》杂志上发表研究报告指出，某些动物体内的甲状腺促进素ＴＳＨ会随着日照时间开始拉长而增加分泌，同时刺激脑部发出“春来了”的讯息，所以ＴＳＨ也可说是生物的“报春荷尔蒙”。
ＴＳＨ向来以调节体温或代谢功能而广为人知，这是首次有研究证实ＴＳＨ对于脑部所产生的影响。此外，继去年春天有其他研究人员发现促使植物开花的荷尔蒙后，这是首次成功发现提醒动物“春天到了”的荷尔蒙。
吉村崇对此表示：“下一步的课题便是弄清制造ＴＳＨ的基因启动机制。若能运用相关研究成果，拉长动物繁殖期，便可能有助于增加畜产量。”此外，该成果也可能会用在容易在特定季节发病的忧郁症等方面的研究。
生物谷推荐原始出处：
Nature 452, 317-322 (20 March 2008) | doi:10.1038/nature06738; Received 22 July 2007; Accepted 25 January 2008
Thyrotrophin in the pars tuberalis triggers photoperiodic response
Nobuhiro Nakao1,11, Hiroko Ono1,11, Takashi Yamamura1, Tsubasa Anraku1, Tsuyoshi Takagi1, Kumiko Higashi1, Shinobu Yasuo1, Yasuhiro Katou1, Saburo Kageyama1, Yumiko Uno1, Takeya Kasukawa2, Masayuki Iigo3, Peter J. Sharp4, Atsushi Iwasawa5, Yutaka Suzuki6, Sumio Sugano6, Teruyuki Niimi7, Makoto Mizutani8, Takao Namikawa8, Shizufumi Ebihara1,8, Hiroki R. Ueda2,9 & Takashi Yoshimura1,8,10
Division of Biomodelling, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
Functional Genomics Subunit, Centre for Developmental Biology, RIKEN, 2-3-3 Minatojima-minamimachi, Chuo-ku, Kobe 650-0047, Japan
Department of Applied Biochemistry, Faculty of Agriculture, Utsunomiya University, 350 Mine-machi, Utsunomiya, 321-8505, Japan
Division of Genetics and Genomics, Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Roslin, Midlothian EH25 9PS, UK
Laboratory of Comparative Biochemistry, Graduate School of Applied Biological Sciences, Gifu University, Gifu 501-1193, Japan
Department of Medical Genome Sciences, Graduate School of Frontier Sciences, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
Division of Biofunctions Development, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
Avian Bioscience Research Centre, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
Laboratory for Systems Biology, Centre for Developmental Biology, RIKEN, 2-3-3 Minatojima-minamimachi, Chuo-ku, Kobe 650-0047, Japan
Institute for Advanced Research, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
These authors contributed equally to this work.
Correspondence to: Takashi Yoshimura1,8,10 Correspondence and requests for materials should be addressed to T.Yo. (Email: takashiy@agr.nagoya-u.ac.jp).
Abstract
Molecular mechanisms regulating animal seasonal breeding in response to changing photoperiod are not well understood. Rapid induction of gene expression of thyroid-hormone-activating enzyme (type 2 deiodinase, DIO2) in the mediobasal hypothalamus (MBH) of the Japanese quail (Coturnix japonica) is the earliest event yet recorded in the photoperiodic signal transduction pathway. Here we show cascades of gene expression in the quail MBH associated with the initiation of photoinduced secretion of luteinizing hormone. We identified two waves of gene expression. The first was initiated about 14 h after dawn of the first long day and included increased thyrotrophin (TSH) -subunit expression in the pars tuberalis; the second occurred approximately 4 h later and included increased expression of DIO2. Intracerebroventricular (ICV) administration of TSH to short-day quail stimulated gonadal growth and expression of DIO2 which was shown to be mediated through a TSH receptor–cyclic AMP (cAMP) signalling pathway. Increased TSH in the pars tuberalis therefore seems to trigger long-day photoinduced seasonal breeding.
