Geiser F, Kenagy G J, Wingfield J C
Department of Zoology, University of Washington, Seattle 98195, USA.
J Comp Physiol B. 1997 Aug;167(6):416-22. doi: 10.1007/s003600050091.
Dietary cholesterol can affect both body lipid composition and steroid hormone concentration. We investigated whether a diet rich in cholesterol influences torpor patterns of hibernating chipmunks (Tamias amoenus) and, if so, whether these changes are better explained by diet-induced changes in body lipid composition or the concentration of testosterone, which at high levels inhibits torpor. Two groups of chipmunks were maintained either on a cholesterol diet (rodent chow containing 10% cholesterol) or a control diet (rodent chow) during pre-hibernation fattening and throughout the hibernation season. Torpid chipmunks on the cholesterol diet had significantly lower minimum body temperatures (-0.2 +/- 0.2 vs -0.6 +/- 0.2 degree C), lower metabolic rates (0.029 +/- 0.002 ml O2 g-1 h-1 vs 0.035 +/- 0.001 ml O2 g-1 h-1), and longer torpor bouts at -1 degree C (6.8 +/- 0.5 vs 4.1 +/- 1.0 days) than chipmunks on the control diet. Dietary cholesterol resulted in a significant increase in blood plasma cholesterol (sevenfold), liver cholesterol content (6.9-fold) and liver triglyceride content (3.5-fold) in comparison to controls. In contrast, dietary cholesterol had no detectable effect on the concentration of plasma testosterone, which was very low in both groups. Since torpor was deeper and longer in animals on the cholesterol diet our study suggests that torpor patterns of chipmunks were either directly affected by the dietary cholesterol or via changes in body lipid composition.
膳食胆固醇会影响身体的脂质组成和类固醇激素浓度。我们研究了富含胆固醇的饮食是否会影响冬眠花栗鼠（美洲花栗鼠）的蛰伏模式，如果是，那么这些变化是由饮食引起的身体脂质组成变化还是睾酮浓度变化（高浓度睾酮会抑制蛰伏）能更好地解释。在冬眠前育肥期和整个冬眠季节，两组花栗鼠分别喂食胆固醇饮食（含10%胆固醇的啮齿动物饲料）或对照饮食（啮齿动物饲料）。与喂食对照饮食的花栗鼠相比，喂食胆固醇饮食的蛰伏花栗鼠的最低体温显著更低（-0.2±0.2℃对-0.6±0.2℃），代谢率更低（0.029±0.002毫升氧气/克-1/小时对0.035±0.001毫升氧气/克-1/小时），在-1℃时的蛰伏时间更长（6.8±0.5天对4.1±1.0天）。与对照组相比，膳食胆固醇导致血浆胆固醇显著增加（7倍）、肝脏胆固醇含量增加（6.9倍）和肝脏甘油三酯含量增加（3.5倍）。相比之下，膳食胆固醇对血浆睾酮浓度没有可检测到的影响，两组的血浆睾酮浓度都非常低。由于喂食胆固醇饮食的动物的蛰伏更深且更长，我们的研究表明花栗鼠的蛰伏模式要么直接受到膳食胆固醇的影响，要么是通过身体脂质组成的变化受到影响。
