Kronfeld-Schor N, Richardson C, Silvia B A, Kunz T H, Widmaier E P
Department of Biology, Boston University, Boston, Massachusetts 02215, USA.
Am J Physiol Regul Integr Comp Physiol. 2000 Oct;279(4):R1277-81. doi: 10.1152/ajpregu.2000.279.4.R1277.
Hibernating animals deposit adipose tissue before hibernation to withstand long periods of reduced energy intake. Normally, adiposity is positively correlated with increased secretion from adipose tissue of the satiety hormone, leptin. During the prehibernatory phase of the little brown bat, Myotis lucifugus, body mass and adiposity increased to a maximum within 12 days. Leptin secretion from adipose tissue in vitro and plasma leptin, however, increased before the increase in adiposity, then significantly decreased when adiposity increased. Basal metabolic rate (BMR) decreased when plasma leptin was increasing. This was followed by an increase in nonshivering thermogenic capacity and brown adipose tissue mass. We conclude that in the early prehibernatory phase, BMR decreases despite increasing plasma leptin levels, suggesting a state of relative leptin resistance at that time. At later stages, adiposity increases as BMR continues to decrease, and plasma leptin becomes dissociated from adiposity. Thus, in M. lucifugus, hibernation may be achieved partly by removing the metabolic signal of leptin during the fattening period of prehibernation.
冬眠动物在冬眠前储存脂肪组织，以承受长时间的能量摄入减少。通常情况下，肥胖程度与脂肪组织分泌的饱腹感激素瘦素的增加呈正相关。在小棕蝠（Myotis lucifugus）的冬眠前期，体重和肥胖程度在12天内增加到最大值。然而，体外脂肪组织的瘦素分泌和血浆瘦素在肥胖程度增加之前就增加了，然后在肥胖程度增加时显著下降。当血浆瘦素增加时，基础代谢率（BMR）下降。随后，非颤抖产热能力和棕色脂肪组织质量增加。我们得出结论，在冬眠前期早期，尽管血浆瘦素水平升高，但基础代谢率仍下降，这表明当时存在相对的瘦素抵抗状态。在后期，随着基础代谢率持续下降，肥胖程度增加，血浆瘦素与肥胖程度分离。因此，在小棕蝠中，冬眠可能部分是通过在冬眠前期的育肥期消除瘦素的代谢信号来实现的。
