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Published on: July 30, 2016
In vitro effect of melatonin on oxygen consumption in liver mitochondria of rats
Carlos F Reyes-Toso1, Conrado R Ricci, Inés R de Mignone
1Departamento de Fisiologia and Hospital de Clinicas, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina.
Objective:
To examine the in vitro effect of melatonin on rat mitochondrial liver respiration.
Methods:
Oxygen consumption by liver mitochondria was measured polarographically in the presence of one of the following Krebs' cycle substrates: Lsuccinate, DL-3- beta-hydroxybutyrate or L-malate. Respiratory velocities at rest (state 4) and during rapid respiration in the presence of substrate and adenosine diphosphate (state 3) were measured in the presence of 10 (-9)-10(-3) M concentrations of melatonin.
Results:
In vitro melatonin (10(-7)-10(-3) M) reduced state 3 mitochondrial respiration. Basal, state 4 respiration was not affected by melatonin. Consequently, control respiratory index (i.e., the ratio of state 3 to state 4 respiration) was inhibited by melatonin with a threshold at 10(-7) M concentration.
Conclusion:
The ability of melatonin to curtail acutely the stimulation of oxygen consumption in liver mitochondria may protect the mitochondria from excessive oxidative damage.