Nogueira-de-Sá Pedro Goes, Bicudo José Eduardo Pereira Wilken, Chaui-Berlinck José Guilherme
Departamento de Fisiologia, Instituto de Biociências da Universidade de São Paulo, São Paulo, Brazil.
School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, Australia.
J Comp Physiol B. 2025 Feb;195(1):81-89. doi: 10.1007/s00360-024-01599-5. Epub 2025 Jan 3.
During the transition from fresh waters to terrestrial habitats, significant adaptive changes occurred in kidney function of vertebrates to cope with varying osmotic challenges. We investigated the mechanisms driving water conservation in the mammalian nephron, focusing on the relative contributions of active ion transport and Starling forces. We constructed a thermodynamic model to estimate the entropy generation associated with different processes within the nephron, and analyzed their relative importance in urine formation. We demonstrate that active ionic reabsorption exerts a pressure above 15,000 torr, a value more than 500 times greater than Starling forces. The entropy generation of the reabsorption process is found to be 20-fold higher than that of renal blood perfusion. These findings imply that the evolutionary history of vertebrates, particularly terrestrial mammals, has shaped the renal architecture to prioritize water conservation by means of an entropically costly process. This approach to the nephron function provides insights into the physiological adaptations of terrestrial vertebrates to conserve water and sheds light on the intricate interplay between environmental conditions and evolutionary responses in renal physiology.
在从淡水环境向陆地栖息地转变的过程中，脊椎动物的肾功能发生了显著的适应性变化，以应对不同的渗透挑战。我们研究了驱动哺乳动物肾单位保水的机制，重点关注主动离子转运和斯塔林力的相对贡献。我们构建了一个热力学模型，以估计与肾单位内不同过程相关的熵产生，并分析它们在尿液形成中的相对重要性。我们证明，主动离子重吸收产生的压力超过15,000托，该值比斯塔林力大500多倍。发现重吸收过程的熵产生比肾血流灌注的熵产生高20倍。这些发现意味着脊椎动物，特别是陆生哺乳动物的进化史，已经塑造了肾脏结构，通过一个熵成本高昂的过程来优先保水。这种对肾单位功能的研究方法为陆生脊椎动物保水的生理适应性提供了见解，并揭示了环境条件与肾脏生理学进化反应之间的复杂相互作用。
