Fig. 1.

Maximal mitochondrial respiration and markers of mitochondrial content. Rates of oxygen consumption (JO₂; A) in permeabilized muscle fibers were determined in men and women with the sequential addition of pyruvate+malate (PM, Complex I), ADP (PMD), glutamate (PMDG, maximal Complex I), and succinate (PMDGS, Complex I+II). Respiratory control ratio (RCR) is complex I respiration in the presence and absence of ADP. B: Western blots were used to estimate the abundance of mitochondrial proteins, as well as proteins involved in regulating mitochondrial biogenesis. GCN5, histone acetyltransferase-5; PDHE1α, pyruvate-dehydrogenase-subunit E1α; PDK4, pyruvate dehydrogenase kinase-4; PGC-1α, peroxisome proliferator-activated receptor γ-coactivator 1-α; PGC-1β, peroxisome proliferator-activated receptor-γ coactivator 1-β; SIRT1, sirtuin-1. C denotes the complex of various subunits of the electron transport chain (CI, CII, CIII, and CV). *Significant difference between men and women (P < 0.05). Data are expressed as means ± SE; n = 7 or 8 participants for each sex.