Johnson Maria S, Onorato David P, Gower Barbara A, Nagy Tim R
Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
Gen Comp Endocrinol. 2004 Mar;136(1):30-6. doi: 10.1016/j.ygcen.2003.11.011.
The aim of this study was to determine whether photoperiod-induced changes in body and fat mass are accompanied by changes in leptin and corticosterone concentrations in collared lemmings. At weaning, eighty male lemmings were maintained in either long photoperiod (LD, n = 40 ) or short photoperiod (SD, n = 40 ). Ten weeks post-weaning lemmings were weighed and assigned to a secondary photoperiod that consisted of either remaining in the same photoperiod or being transferred to the alternate photoperiod (LD-LD, LD-SD, SD-SD, and SD-LD; n = 20 per group). Ten days post-switch, half the animals from each group were sacrificed. The remaining animals were sacrificed on day 21 post-switch. Blood was collected for determination of serum leptin and corticosterone, and carcasses were analyzed for body composition. LD-SD lemmings gained the most weight, whilst SD-LD lemmings lost weight. SD-LD lemmings had significantly lower leptin levels relative to fat mass than SD-SD lemmings. Corticosterone levels were higher in the SD-LD than SD-SD lemmings on both days 10 and 21. Levels were not significantly different between LD-LD and LD-SD lemmings; however by day 21 the levels were slightly lower in the LD-SD lemmings. Discussion. Lemmings showed seasonally appropriate body weight changes in response to the changing photoperiod. Weight loss was associated with higher corticosterone, and lower leptin levels adjusted for fat mass. Neither relative leptin levels, nor corticosterone levels changed significantly with weight gain. Our results indicate that corticosterone and leptin are associated more with seasonal weight loss than weight gain in lemmings.
本研究的目的是确定在领旅鼠中，光周期诱导的身体和脂肪量变化是否伴随着瘦素和皮质酮浓度的变化。断奶时，将80只雄性旅鼠分别饲养在长光周期（LD，n = 40）或短光周期（SD，n = 40）环境中。断奶后10周，对旅鼠进行称重，并将其分配到第二个光周期环境中，即要么保持在相同的光周期环境中，要么转移到交替的光周期环境中（LD-LD、LD-SD、SD-SD和SD-LD；每组n = 20）。转换光周期10天后，每组一半的动物被处死。其余动物在转换光周期21天后被处死。采集血液以测定血清瘦素和皮质酮，并对尸体进行身体成分分析。LD-SD组的旅鼠体重增加最多，而SD-LD组的旅鼠体重减轻。相对于脂肪量，SD-LD组旅鼠的瘦素水平显著低于SD-SD组旅鼠。在第10天和第21天，SD-LD组旅鼠的皮质酮水平均高于SD-SD组旅鼠。LD-LD组和LD-SD组旅鼠的皮质酮水平无显著差异；然而，到第21天时，LD-SD组旅鼠的皮质酮水平略低。讨论。旅鼠表现出随光周期变化而出现的季节性适宜体重变化。体重减轻与较高的皮质酮水平以及根据脂肪量调整后的较低瘦素水平相关。体重增加时，相对瘦素水平和皮质酮水平均无显著变化。我们的结果表明，在旅鼠中，皮质酮和瘦素与季节性体重减轻的关联比与体重增加的关联更大。
