POSSIBLE ROLE OF INTRACELLULAR POLYAMINES IN MITOCHONDRIAL METABOLIC-REGULATION

Studies were made on the effects of very low concentrations of the polyamine, spermine, on rat liver mitochondrial metabolism associated with β-hydroxybutyrate. The respiratory control ratio and the rate of respiration during ADP-ATP conversion are significantly altered with shifts in spermine concentrations of as little as 15.7 nMoles/ml within the physiological Mg++ concentration range. These spermine concentration changes are small compared to the estimated hepatic intracellular levels of spermine which have been reported to be between 200 and 1200 nMoles/gm wet weight under normal conditions. There is now evidence that exposure of an animal to certain environmental conditions induces changes of 164 nMoles/gm wet weight in intracellular levels of liver spermine in a few hours. Also there is evidence that the concentration of intracellular polyamines is influenced by endocrines since the levels of the enzymes responsible for their synthesis are markedly affected by hormonal changes. Therefore, alterations of polyamine levels may play a role in mitochondrial metabolic regulation in vivo. © 1979.