Effect of melatonin treatment on oxygen consumption by rat liver mitochondria.
The objective of this study was to examine the in vivo effect of melatonin on rat mitochondrial liver respiration. Two experiments were performed: For experiment 1, adult male rats received melatonin in the drinking water (16 or 50 microg/ml) or vehicle during 45 days. For experiment 2, rats received melatonin in the drinking water (50 microg/ml) for 45 days, or the same amount for 30 days followed by a 15 day-withdrawal period. At sacrifice, a liver mitochondrial fraction was prepared and oxygen consumption was measured polarographically in the presence of excess concentration of DL-3-beta-hydroxybutyrate or L-succinate. Melatonin treatment decreased Krebs' cycle substrate-induced respiration significantly at both examined doses. The stimulation of mitochondrial respiration caused by excess concentration of substrate recovered after melatonin withdrawal. Basal state 4 respiration was not modified by melatonin. Melatonin, by curtailing overstimulation of cellular respiration caused by excess Krebs' cycle substrates, can protect the mitochondria from oxidative damage.
Departamento de Fisiología and Hospital de Clínicas, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina.
C F
CF
Reyes-Toso
I R
IR
Rebagliati
C R
CR
Ricci
L M
LM
Linares
L E
LE
Albornoz
D P
DP
Cardinali
A
A
Zaninovich
D020155:3-Hydroxybutyric Acid / Q000378:metabolism; D000818:Animals; D019069:Cell Respiration / Q000187:drug effects*; D002952:Citric Acid Cycle / Q000187:drug effects*; D008297:Male; D008550:Melatonin / Q000494:pharmacology*; D008930:Mitochondria, Liver / Q000187:drug effects / Q000378:metabolism*; D010101:Oxygen Consumption / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D019802:Succinic Acid / Q000378:metabolism
D019802:Succinic Acid; D008550:Melatonin; D020155:3-Hydroxybutyric Acid