RT Journal Article
SR Electronic
T1 Threshold effect in the H2O2 production of skeletal muscle mitochondria during fasting and refeeding
JF The Journal of Experimental Biology
JO J. Exp. Biol.
FD The Company of Biologists Ltd
SP jeb196188
DO 10.1242/jeb.196188
VO 222
IS 4
A1 Roussel, Damien
A1 Boël, Mélanie
A1 Mortz, Mathieu
A1 Romestaing, Caroline
A1 Duchamp, Claude
A1 Voituron, Yann
YR 2019
UL http://jeb.biologists.org/content/222/4/jeb196188.abstract
AB Under nutritional deprivation, the energetic benefits of reducing mitochondrial metabolism are often associated with enhanced harmful pro-oxidant effects and a subsequent long-term negative impact on cellular integrity. However, the flexibility of mitochondrial functioning under stress has rarely been explored during the transition from basal non-phosphorylating to maximal phosphorylating oxygen consumption. Here, we experimentally tested whether ducklings (Cairina moschata), fasted for 6 days and subsequently refed for 3 days, exhibited modifications to their mitochondrial fluxes, i.e. oxygen consumption, ATP synthesis, reactive oxygen species generation (ROS) and associated ratios, such as the electron leak (% ROS/O) and the oxidative cost of ATP production (% ROS/ATP). This was carried out at different steady-state rates of oxidative phosphorylation in both pectoralis (glycolytic) and gastrocnemius (oxidative) muscles. Fasting induced a decrease in the rates of oxidative phosphorylation and maximal ROS release. These changes were completely reversed by 3 days of refeeding. Yet, the fundamental finding of the present study was the existence of a clear threshold in ROS release and associated ratios, which remained low until a low level of mitochondrial activity was reached (30–40% of maximal oxidative phosphorylation activity).