This Article Full Text Full Text (PDF) All Versions of this Article: 147/1/432    most recent Author Manuscript (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Yasuo, S. Articles by Yoshimura, T. Search for Related Content PubMed PubMed Citation Articles by Yasuo, S. Articles by Yoshimura, T.

Long-Day Suppressed Expression of Type 2 Deiodinase Gene in the Mediobasal Hypothalamus of the Saanen Goat, a Short-Day Breeder: Implication for Seasonal Window of Thyroid Hormone Action on Reproductive Neuroendocrine Axis

Division of Biomodeling (S.Y., N.N., T.Ya., M.W., T.W., S.E., T.Yo.), Laboratory of Animal Management and Resources (S.-i.O.), Division of Applied Genetics and Physiology (K.-i.M.), Graduate School of Bioagricultural Sciences, Technical Center (S.H., A.G., H.A.), and Institute for Advanced Research (T.Yo.), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan; Laboratory of Neuroendocrinology (S.O., H.O.), National Institute of Agrobiological Sciences, Ikenodai, Tsukuba 305-8602, Japan; and Department of Applied Biological Chemistry (M.I.), Faculty of Agriculture, Utsunomiya University, Mine-machi, Utsunomiya, Tochigi 321-8505, Japan; and Medical Research Council Human Reproductive Sciences Unit (G.A.L.), University of Edinburgh, Chancellor’s Building, Edinburgh EH16 4SB, Scotland, United Kingdom

Address all correspondence and requests for reprints to: Takashi Yoshimura, Ph.D., Division of Biomodeling, Graduate School of Bioagricultural Sciences, & Institute for Advanced Research, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan. E-mail: takashiy{at}agr.nagoya-u.ac.jp.

In most animals that live in temperate regions, reproduction is under photoperiodic control. In long-day breeders such as Japanese quail and Djungarian hamsters, type 2 deiodinase (Dio2) plays an important role in the mediobasal hypothalamus, catalyzing the conversion of prohormone T₄ to bioactive T₃ to regulate the photoperiodic response of the gonads. However, the molecular basis for seasonal reproduction in short-day breeders remains unclear. Because thyroid hormones are also known to be involved in short-day breeders, we examined the effect of an artificial long-day stimulus on Dio2 expression in the male Saanen goat (Capra hircus), a short-day breeder. Dio2 expression was observed in the caudal continuation of the arcuate nucleus, known as the target site for both melatonin and T₄ action. In addition, expression of Dio2 and T₃ content in the mediobasal hypothalamus was suppressed by artificial long-day conditions, which is the opposite of the results of long-day breeders. Thyroid hormone action on the development of neuroendocrine anestrus is known to be limited to a specific seasonal window. This long-day suppression of Dio2 may provide a mechanism that accounts for the lack of responsiveness to thyroxine during the mid to late anestrus.

This article has been cited by other articles:

				N. Nakao, H. Ono, and T. Yoshimura Thyroid hormones and seasonal reproductive neuroendocrine interactions Reproduction, July 1, 2008; 136(1): 1 - 8. [Abstract] [Full Text] [PDF]

				D. A. Bechtold and A. S. I. Loudon Hypothalamic Thyroid Hormones: Mediators of Seasonal Physiology Endocrinology, August 1, 2007; 148(8): 3605 - 3607. [Full Text] [PDF]

				P. Barrett, F. J. P. Ebling, S. Schuhler, D. Wilson, A. W. Ross, A. Warner, P. Jethwa, A. Boelen, T. J. Visser, D. M. Ozanne, et al. Hypothalamic Thyroid Hormone Catabolism Acts as a Gatekeeper for the Seasonal Control of Body Weight and Reproduction Endocrinology, August 1, 2007; 148(8): 3608 - 3617. [Abstract] [Full Text] [PDF]

				D. A. Freeman, B. J. W. Teubner, C. D. Smith, and B. J. Prendergast Exogenous T3 mimics long day lengths in Siberian hamsters Am J Physiol Regulatory Integrative Comp Physiol, June 1, 2007; 292(6): R2368 - R2372. [Abstract] [Full Text] [PDF]

				T. Watanabe, T. Yamamura, M. Watanabe, S. Yasuo, N. Nakao, A. Dawson, S. Ebihara, and T. Yoshimura Hypothalamic expression of thyroid hormone-activating and -inactivating enzyme genes in relation to photorefractoriness in birds and mammals Am J Physiol Regulatory Integrative Comp Physiol, January 1, 2007; 292(1): R568 - R572. [Abstract] [Full Text] [PDF]

				F. G. Revel, M. Saboureau, P. Pevet, J. D. Mikkelsen, and V. Simonneaux Melatonin Regulates Type 2 Deiodinase Gene Expression in the Syrian Hamster Endocrinology, October 1, 2006; 147(10): 4680 - 4687. [Abstract] [Full Text] [PDF]