Cossin-Sevrin Nina, Bocquet Céline, Lemonnier Camille, Faulmann Thomas, Garcin Natacha, Lejeune Mathilde, Bize Pierre, Robin Jean-Patrice, Anttila Katja, Ruuskanen Suvi, Viblanc Vincent A
Ecol Evol Physiol. 2025 Mar-Apr;98(2):96-110. doi: 10.1086/736013. Epub 2025 May 28.
AbstractBecause of their extended fasting period on land during breeding, male king penguins have been extensively studied in order to unravel the physiological adaptations that enable them to fast while having to find a partner, defend their territory, or brood their offspring. While the different phases of fasting and the nature of the metabolic fuels used are well characterized in male king penguins, few studies have focused on the efficiency of the conversion of the metabolic resources into energy at a cellular level through mitochondrial respiration. Furthermore, little information is available on females in general while they experience fasting periods. Here, we measured mitochondrial respiration rates of red blood cells (RBCs) at the beginning (3 d) and end (10 d) of a natural egg-incubation fast in male and female king penguins. We tested whether RBC mitochondrial metabolism and its efficiency are modulated by fasting duration in free-living king penguins but also assessed whether this modulation is sex specific. In response to fasting, the respiration allocated to ATP synthesis in RBCs decreased in both sexes. Interestingly, RBC mitochondrial metabolic rates were higher in females at any stage of fasting. Furthermore, RBC mitochondrial metabolism efficiency decreased in males after 10 d of fasting but remained constant in females. Our results demonstrate that RBC mitochondrial metabolism is context and state dependent, differing between sexes and changing with fasting. They underline the importance of taking both sexes into account in physiological studies, where females remain underrepresented.
摘要
由于雄性帝企鹅在繁殖期于陆地上长时间禁食，为了弄清楚它们在寻找配偶、保卫领地或孵育后代时能够禁食的生理适应性，人们对其进行了广泛研究。虽然雄性帝企鹅禁食的不同阶段以及所使用代谢燃料的性质已得到充分描述，但很少有研究关注通过线粒体呼吸在细胞水平上将代谢资源转化为能量的效率。此外，关于雌性帝企鹅在禁食期的情况，总体上了解甚少。在此，我们测量了雄性和雌性帝企鹅在自然孵卵禁食开始时（3天）和结束时（10天）红细胞的线粒体呼吸速率。我们测试了自由生活的帝企鹅红细胞线粒体代谢及其效率是否受禁食持续时间的调节，还评估了这种调节是否具有性别特异性。对禁食的反应是，两性红细胞中分配给ATP合成的呼吸作用均下降。有趣的是，在禁食的任何阶段，雌性的红细胞线粒体代谢率都更高。此外，禁食10天后雄性红细胞线粒体代谢效率下降，而雌性则保持不变。我们的结果表明，红细胞线粒体代谢取决于环境和状态，存在性别差异并随禁食而变化。这些结果强调了在生理学研究中考虑两性的重要性，目前在这些研究中雌性的代表性仍然不足。
