Administration of hepatotoxic doses of carbon tetrachloride to mice produced a 25-fold increase in spermidine/spermine N1-acetyltransferase activity within 6 h, but did not significantly change the activity of polyamine oxidase. The content of acetylated polyamines in the mouse liver was increased more than 100-fold from levels below the limit of detection to 0.6 μmol of N1-acetylspermidine and 0.045 μmol of N1-acetylspermine per gram of tissue. Putrescine levels also rose by 7-fold within 6 h and by 21-fold within 24 h. These results are in contrast to changes in hepatic polyamines brought about in the rat by carbon tetrachloride. Although the hepatotoxin produced a similar increase in spermidine/spermine N1-acetyltransferase in this species, the rise in acetylated polyamines was much smaller and more transient. The content of N1-acetylspermidine was increased only to 0.066 μmol/g and N1-acetylspermine was not detected. However, in the rat putrescine increased 35-fold within 6 h and 64-fold by 16 h. These differences appear to be due to the much higher polyamine oxidase activity which was 20 times greater in the rat than in the mouse liver. This oxidase converts N1-acetylspermine to spermidine and degrades N1-acetylspermidine to putrescine. Spermine content was significantly reduced in both species after exposure to carbon tetrachloride, but only part of this decline could be attributed to the increased acetylation.
All Science Journal Classification (ASJC) codes
- Molecular Biology