Inhibition of putrescine aminopropyltransferase influences rat liver regeneration.

A close relationship between rat liver regeneration and the concentration ratio of spermidine to spermine (spd:spm) was demonstrated by the oral administration of trans-4-methylcyclohexylamine (MCHA), a specific inhibitor of putrescine aminopropyltransferase. A decrease in recovery rate of remnant liver with MCHA, as a percentage index of remnant liver weight to body weight, correlated well with a decrease of the spd:spm value, with a correlation coefficient of 0.952 for the remnant livers on day 3 after partial hepatectomy. The decrease in recovery rate could be explained by a prolonged cell cycle based on the data of the proliferating cell nuclear antigen labelling index and mitotic cell index in both livers of day 2 and day 3 after partial hepatectomy. The results presented here will give a new aspect in the field of polyamine regulation to control cell growth in vivo.