Kriegsfeld L J, Nelson R J
Department of Psychology, The Johns Hopkins University, Baltimore, Maryland 21218-2686, USA.
J Pineal Res. 1998 Sep;25(2):101-5. doi: 10.1111/j.1600-079x.1998.tb00546.x.
Cessation of breeding is central among the suite of winter-coping strategies used by small rodents to survive energy-demanding winter conditions. Animals use photoperiod to predict the onset of winter and initiate, well in advance of deteriorating conditions, seasonal adaptations. Exposure to short photoperiod leads to regression of the reproductive system in long-day breeding animals. Likewise, exposure to short days leads to enhanced immune function among several rodent species studied. Because dehydroepiandrosterone (DHEA) increases immune function in virtually all studies reported to date, we sought to determine if DHEA concentrations might be influenced by photoperiod, thereby suggesting a mechanism whereby short photoperiod may enhance immune function. Male deer mice (Peromyscus maniculatus) were exposed to either short or long days for 10 weeks. Short photoperiods caused significant reduction in all reproductive organs measured relative to animals housed in long days. However, DHEA concentrations did not differ between short- and long-day mice. Taken together, these data suggest that short-day enhancement of immune function in deer mice is independent of DHEA concentrations.
停止繁殖是小型啮齿动物为在对能量需求极高的冬季条件下生存而采用的一系列冬季应对策略中的核心。动物利用光周期来预测冬季的到来，并在条件恶化之前很早就开始启动季节性适应。暴露于短光周期会导致长日照繁殖动物的生殖系统退化。同样，在几种被研究的啮齿动物物种中，暴露于短日照会增强免疫功能。由于到目前为止几乎所有报道的研究中脱氢表雄酮（DHEA）都会增强免疫功能，我们试图确定DHEA浓度是否可能受光周期影响，从而揭示一种短光周期可能增强免疫功能的机制。雄性鹿鼠（白足鼠）被暴露于短日照或长日照环境中10周。与处于长日照环境中的动物相比，短光周期导致所测量的所有生殖器官显著缩小。然而，短日照和长日照小鼠的DHEA浓度并无差异。综合这些数据表明，鹿鼠短日照条件下免疫功能的增强与DHEA浓度无关。
