Bailey Allison M, Legan Sandra J, Meretsky Vicky J, Demas Gregory E
Department of Biology, Indiana University, 1001 E 3rd St., Bloomington, IN, USA.
Department of Physiology, University of Kentucky, 508 Medical Science Building, Lexington, KY, USA.
Gen Comp Endocrinol. 2017 Sep 1;250:95-103. doi: 10.1016/j.ygcen.2017.06.004. Epub 2017 Jun 12.
Animals living in temperate climates respond to environmental cues that signal current and future resource availability to ensure that energy resources are available to support reproduction. Siberian hamsters (Phodopus sungorus) undergo robust gonadal regression in short, winter-like photoperiods as well as in response to mild food restriction in intermediate photoperiods. The goal of the present study was to investigate whether leptin is a relevant metabolic signal in regulating gonadal regression in response to diminishing food availability. Adult female hamsters housed in short-day (winter-like) or intermediate (fall-like) photoperiods received either ad libitum access to food or mild food restriction (90% of ad libitum intake) and were treated with either leptin or a vehicle for five weeks in order to determine the ability of leptin to inhibit gonadal regression. At the end of five weeks, vehicle-treated hamsters showed physiological signs associated with ongoing gonadal regression, such as decreases in body mass and food intake, cessation of estrous cycling, and small decreases in reproductive tissue mass. Leptin did not modify changes in body mass, food intake, hormone concentration, or tissue mass, but showed a tendency to support estrous cycling, particularly in response to food restriction in the intermediate photoperiod treatment. Overall, leptin appears to play a minor role in coordinating reproductive responses to multiple environmental cues, at least in the early stages of gonadal regression.
生活在温带气候中的动物会对环境线索做出反应，这些线索会提示当前和未来的资源可用性，以确保有能量资源来支持繁殖。西伯利亚仓鼠（Phodopus sungorus）在短的、类似冬季的光周期以及在中间光周期中对轻度食物限制的反应下，会经历强烈的性腺退化。本研究的目的是调查瘦素是否是在食物供应减少时调节性腺退化的相关代谢信号。饲养在短日照（类似冬季）或中间日照（类似秋季）光周期下的成年雌性仓鼠，要么可以随意获取食物，要么受到轻度食物限制（随意摄入量的90%），并接受瘦素或载体处理五周，以确定瘦素抑制性腺退化的能力。在五周结束时，接受载体处理的仓鼠表现出与正在进行的性腺退化相关的生理迹象，如体重和食物摄入量下降、发情周期停止以及生殖组织质量略有下降。瘦素并没有改变体重、食物摄入量、激素浓度或组织质量的变化，但显示出支持发情周期的趋势，特别是在中间光周期处理中对食物限制的反应。总体而言，至少在性腺退化的早期阶段，瘦素似乎在协调对多种环境线索的生殖反应中起次要作用。
