Yasuo Shinobu, Watanabe Miwa, Iigo Masayuki, Nakamura Takahiro J, Watanabe Tsuyoshi, Takagi Tsuyoshi, Ono Hiroko, Ebihara Shizufumi, Yoshimura Takashi
Division of Biomodeling, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.
Am J Physiol Regul Integr Comp Physiol. 2007 Mar;292(3):R1315-9. doi: 10.1152/ajpregu.00396.2006. Epub 2006 Nov 16.
The molecular basis of seasonal or nonseasonal breeding remains unknown. Although laboratory rats are generally regarded as photoperiod-insensitive species, the testicular weight of the Fischer 344 (F344) strain responds to photoperiod. Recently, it was clarified that photoperiodic regulation of type 2 iodothyronine deiodinase (Dio2) in the mediobasal hypothalamus (MBH) is critical in photoperiodic gonadal regulation. Strain-dependent differences in photoperiod sensitivity may now provide the opportunity to address the regulatory mechanism of seasonality by studying Dio2 expression. Therefore, in the present study, we examined the effect of photoperiod on Dio2 expression in photoperiod-sensitive F344 and photoperiod-insensitive Wistar rats. A statistically significant difference was observed between short and long days in terms of testicular weight and Dio2 expression in the F344 strain, while no difference was observed in the Wistar strain. These results suggest that differential responses of the Dio2 gene to photoperiod may determine the strain-dependent differences in photoperiod sensitivity in laboratory rats.
季节性或非季节性繁殖的分子基础仍然未知。尽管实验室大鼠通常被认为是对光周期不敏感的物种，但Fischer 344（F344）品系的睾丸重量会对光周期作出反应。最近，有研究表明，中基底下丘脑（MBH）中2型碘甲状腺原氨酸脱碘酶（Dio2）的光周期调节在光周期性腺调节中起关键作用。光周期敏感性的品系依赖性差异现在可能为通过研究Dio2表达来探讨季节性调节机制提供机会。因此，在本研究中，我们研究了光周期对光周期敏感的F344大鼠和光周期不敏感的Wistar大鼠中Dio2表达的影响。在F344品系中，短日照和长日照之间在睾丸重量和Dio2表达方面存在统计学上的显著差异，而在Wistar品系中未观察到差异。这些结果表明，Dio2基因对光周期的不同反应可能决定了实验室大鼠光周期敏感性的品系依赖性差异。
