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Phylogenetic differences of mammalian basal metabolic rate are not explained by mitochondrial basal proton leak
journal contribution
posted on 2023-05-17, 10:14 authored by Elias Polymeropoulos, Heldmaier, G, Peter FrappellPeter Frappell, McAllan, BM, Withers, KW, Klingenspor, M, White, CR, Jastroch, MMetabolic rates of mammals presumably increased during the evolution of endothermy, but molecular and cellular mechanisms underlying basal metabolic rate (BMR) are still not understood. It has been established that mitochondrial basal proton leak contributes significantly to BMR. Comparative studies among a diversity of eutherian mammals showed that BMR correlates with body mass and proton leak. Here, we studied BMR and mitochondrial basal proton leak in liver of various marsupial species. Surprisingly, we found that the mitochondrial proton leak was greater in marsupials than in eutherians, although marsupials have lower BMRs. To verify our finding, we kept similar-sized individuals of a marsupial opossum (Monodelphis domestica) and a eutherian rodent (Mesocricetus auratus) species under identical conditions, and directly compared BMR and basal proton leak. We confirmed an approximately 40 per cent lower mass specific BMR in the opossum although its proton leak was significantly higher (approx. 60%). We demonstrate that the increase in BMR during eutherian evolution is not based on a general increase in the mitochondrial proton leak, although there is a similar allometric relationship of proton leak and BMR within mammalian groups. The difference in proton leak between endothermic groups may assist in elucidating distinct metabolic and habitat requirements that have evolved during mammalian divergence.
History
Publication title
Royal Society of London. Proceedings B. Biological SciencesVolume
279Issue
1726Pagination
185-193ISSN
0962-8452Department/School
School of Natural SciencesPublisher
The Royal Society PublishingPlace of publication
6-9 Carlton House Terrace, London, SW1Y 5AG, UKRights statement
Copyright 2011 The Royal SocietyRepository Status
- Restricted