Ono Hiroko, Nakao Nobuhiro, Yoshimura Takashi
Laboratory of Animal Physiology, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.
Gen Comp Endocrinol. 2009 Sep 1;163(1-2):2-6. doi: 10.1016/j.ygcen.2008.11.017. Epub 2008 Dec 3.
Animals measure photoperiod (daylength) and adapt to seasonal changes in the environment by altering their physiology and behavior accordingly. Although this photoperiodic response has long been of interest, the underlying mechanism has only recently begun to be uncovered at the molecular level. Japanese quail provide an excellent model to study the molecular mechanism underlying the vertebrate photoperiodic response. The recent sequencing of the chicken genome allowed a system-level analysis of photoperiodic time measurement in quail, and this approach uncovered the key event in the photoperiodic signaling cascade that regulates seasonal reproduction. Long photoperiod-induced expression of thyrotropin in the pars tuberalis of the pituitary gland was found to trigger local thyroid hormone catabolism in the mediobasal hypothalamus, which increases the activity of the reproductive neuroendocrine system resulting in gonadal development. Since thyrotropin was only known to stimulate the thyroid gland, a traditional hypothesis-driven approach would not have been expected to predict this discovery. Thus, a functional genomics approach, which is a discovery-driven approach, provides new insights in the field of endocrinology.
动物通过测量光周期（日照长度），并相应地改变其生理和行为来适应环境中的季节性变化。尽管这种光周期反应长期以来一直备受关注，但其潜在机制直到最近才在分子水平上开始被揭示。日本鹌鹑为研究脊椎动物光周期反应的分子机制提供了一个极佳的模型。鸡基因组的近期测序使得对鹌鹑光周期时间测量进行系统水平的分析成为可能，这种方法揭示了调节季节性繁殖的光周期信号级联反应中的关键事件。研究发现，长光周期诱导垂体结节部促甲状腺激素的表达，进而触发中基底下丘脑局部甲状腺激素的分解代谢，这会增强生殖神经内分泌系统的活性，从而导致性腺发育。由于促甲状腺激素一直被认为仅能刺激甲状腺，传统的基于假设驱动的方法不太可能预测到这一发现。因此，功能基因组学方法，一种基于发现驱动的方法，为内分泌学领域提供了新的见解。
