RT Journal Article
SR Electronic
T1 Threshold effect in the H<sub>2</sub>O<sub>2</sub> 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).