Laboratoire d'Ecologie des Hydrosystèmes Naturels et Anthropisés (U.M.R. CNRS 5023), Université Claude Bernard Lyon1, Université de Lyon, Bd du 11 novembre 1918, Bât. Darwin C, 69622, Villeurbanne Cedex, France.
Sorbonne Université, CNRS, IRD, INRA, Institut d'écologie Et Des Sciences de L'environnement (IEES), Paris, France.
J Comp Physiol B. 2022 Nov;192(6):765-774. doi: 10.1007/s00360-022-01454-5. Epub 2022 Aug 3.
Stress hormones and their impacts on whole organism metabolic rates are usually considered as appropriate proxies for animal energy budget that is the foundation of numerous concepts and models aiming at predicting individual and population responses to environmental stress. However, the dynamics of energy re-allocation under stress make the link between metabolism and corticosterone complex and still unclear. Using ectopic application of corticosterone for 3, 11 and 21 days, we estimated a time effect of stress in a lizard (Zootoca vivipara). We then investigated whole organism metabolism, muscle cellular O consumption and liver mitochondrial oxidative phosphorylation processes (O consumption and ATP production) and ROS production. The data showed that while skeletal muscle is not impacted, stress regulates the liver mitochondrial functionality in a time-dependent manner with opposing pictures between the different time expositions to corticosterone. While 3 days exposition is characterized by lower ATP synthesis rate and high HO release with no change in the rate of oxygen consumption, the 11 days exposition reduced all three fluxes of about 50%. Oxidative phosphorylation capacities in liver mitochondria of lizard treated with corticosterone for 21 days was similar to the hepatic mitochondrial capacities in lizards that received no corticosterone treatment but with 40% decrease in HO production. This new mitochondrial functioning allows a better capacity to respond to the energetic demands imposed by the environment but do not influence whole organism metabolism. In conclusion, global mitochondrial functioning has to be considered to better understand the proximal causes of the energy budget under stressful periods.
应激激素及其对整体生物代谢率的影响通常被认为是动物能量预算的合适替代指标，而能量预算是许多旨在预测个体和种群对环境压力反应的概念和模型的基础。然而，应激下能量再分配的动态使得代谢和皮质酮之间的联系变得复杂且仍不清楚。我们使用皮质酮的异位应用 3、11 和 21 天来估计蜥蜴（Zootoca vivipara）中的应激时间效应。然后，我们研究了整体生物代谢、肌肉细胞 O 消耗和肝脏线粒体氧化磷酸化过程（O 消耗和 ATP 产生）和 ROS 产生。数据表明，虽然骨骼肌不受影响，但应激以时间依赖的方式调节肝脏线粒体功能，皮质酮不同时间暴露的结果相反。虽然 3 天暴露的特点是 ATP 合成速率较低，HO 释放较高，而 O 消耗速率不变，但 11 天暴露使所有三种通量降低了约 50%。用皮质酮处理 21 天的蜥蜴的肝脏线粒体氧化磷酸化能力与未接受皮质酮处理的蜥蜴的肝脏线粒体能力相似，但 HO 产生减少了 40%。这种新的线粒体功能使蜥蜴能够更好地应对环境施加的能量需求，但不影响整体生物代谢。总之，必须考虑整体线粒体功能，以更好地理解应激期能量预算的近端原因。
