Substrate-dependent effect of phenolic antioxidants on Ca2+ accumulation by rat liver mitochondria.
The effect of different phenolic antioxidants on mitochondrial Ca2+ capacity (maximum amount of Ca2+ mitochondria can accumulate) was studied. Butylated hydroxytoluene substantially enhanced the Ca2+ capacity in mitochondria oxidizing succinate, butylated hydroxyanisole had a moderate effect while 2,5-di-(t-butyl)- 1,4 benzohydroquinone did not affect Ca2+ capacity at all. The analysis of Ca2+ accumulation in mitochondria oxidizing succinate in the presence of 2,5-di-(t-butyl)-1,4 benzohydroquinone revealed inhibition of the rate of Ca2+ accumulation. This effect was absent when ATP hydrolysis or NAD+-dependent substrate oxidation supported Ca2+ transport. Direct measurements of oxygen consumption revealed the concentration-dependent inhibition of succinate oxidation by increasing concentrations of 2,5-di-(t-butyl)- 1,4 benzohydroquinone. When succinate was substituted by NAD+-dependent respiratory substrates, the Ca2+ capacity of mitochondria with 2,5-di-(t-butyl)-1,4 benzohydroquinone was even higher than in the presence of butylated hydroxytoluene.
Ryan
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S
Institute of Theoretical and Experimental Biophysics, Pushchino, Russia.
Gogvadze
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V
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D002083:Butylated Hydroxyanisole / Q000031:analogs & derivatives / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D008930:Mitochondria, Liver / Q000378:metabolism*; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D010101:Oxygen Consumption; D051381:Rats; D013379:Substrate Specificity
D000975:Antioxidants; D002083:Butylated Hydroxyanisole; D002118:Calcium