Polyamine effects on succinate-linked and αketoglutarate-linked rat liver mitochondrial respiration

Abstract

Summary At 0.6–1.17 mM Mg ++ , physiological spermine levels strikingly enhance respiratory control ratios of rat liver mitochondria with αketoglutarate by suppressing respiration which occurs after added ADP is converted to ATP. Respiration with added ADP is enhanced at 0.6 but not at 1.17 mM Mg ++ . Conversely, with succinate, spermine at high concentrations depresses respiratory control ratios but only slightly affects respiration. Spermidine with αketoglutarate increases respiratory control ratios but suppresses respiration both during and after added ADP-ATP conversion. However, suppression is greater after this conversion. With succinate, spermidine also increases respiratory control but its effects on respiration during or after added ADP-ATP conversion vary with Mg ++ concentration. Thus, polyamines seem to affect mitochondrial metabolism.