Polyamines and their biosynthetic decarboxylases in various tissues of the young rat during recovery from undernutrition

Abstract

Weanling male and female rats were undernourished for 4 wk and then rehabilitated by allowing ad lib feeding. During rehabilitation polyamine-biosynthetic enzymes were examined in the liver, spleen and quadriceps and gastrocnemius muscles. During the first few hours of rehabilitation there was a marked increase in liver weight, accompanied by a very marked increase in ornithine decarboxylase activity. Increases in the activity of this enzyme in other tissues did not occur until between 2-7 days of rehabilitation, at which time there were further increases in enzyme activity in the liver. S-Adenosylmethionine decarboxylase activity also showed marked fluctuations in activity in all the tissues examined. Hepatic putrescine and spermidine concentrations also varied during rehabilitation, but spermine concentration remained relatively constant. Both spermine and spermidine were at normal concentrations in the liver from the 10th day of rehabilitation onwards. In all of the tissues examined there were marked sex differences in the parameters studied, particularly in splenic and muscular ornithine decarboxylase activity. In the tissues of the male rats, changes in polyamine synthesis paralleled changes in nucleic acid and protein synthesis.