AUTHOR=Cardinale Daniele A. , Larsen Filip J. , Schiffer Tomas A. , Morales-Alamo David , Ekblom Björn , Calbet Jose A. L. , Holmberg Hans-Christer , Boushel Robert 

TITLE=Superior Intrinsic Mitochondrial Respiration in Women Than in Men

JOURNAL=Frontiers in Physiology

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2018.01133

DOI=10.3389/fphys.2018.01133

ISSN=1664-042X

ABSTRACT=<p>Sexual dimorphism is apparent in humans, however, to date no studies have investigated mitochondrial function focusing on intrinsic mitochondrial respiration (i.e., mitochondrial respiration for a given amount of mitochondrial protein) and mitochondrial oxygen affinity (p50<sub>mito</sub>) in relation to biological sex in human. A skeletal muscle biopsy was donated by nine active women, and ten men matched for maximal oxygen consumption (VO<sub>2max</sub>) and by nine endurance trained men. Intrinsic mitochondrial respiration, assessed in isolated mitochondria, was higher in women compared to men when activating complex I (CI<sub>P</sub>) and complex I+II (CI+II<sub>P</sub>) (<italic>p</italic> &lt; 0.05), and was similar to trained men (CI<sub>P</sub>, <italic>p</italic> = 0.053; CI+II<sub>P</sub>, <italic>p</italic> = 0.066). Proton leak and p50<sub>mito</sub> were higher in women compared to men independent of VO<sub>2max</sub>. In conclusion, significant novel differences in mitochondrial oxidative function, intrinsic mitochondrial respiration and p50<sub>mito</sub> exist between women and men. These findings may represent an adaptation in the oxygen cascade in women to optimize muscle oxygen uptake to compensate for a lower oxygen delivery during exercise.</p>