Abstract
In rats, effects of starvation and subsequent refeeding on hepatic polyamine-synthesizing
enzymes (ornithine decarboxylase, S-adenosyl-methionine decarboxylase) and on polyamine
contents (putrescine, spermidine, spermine), were examined. Following 12 hours of
starvation, ornithine decarboxylase activity was reduced markedly (to 13% of controls)
and was decreased to levels near zero after 3 days of starvation, whereas S-adenosylmethionine
decarboxylase activity declined less drastically (to 50% of controls). This fall in
enzyme activities was in good accord with putrescine and spermidine contents which
were found to be decreased significantly in rat livers under these conditions. On
refeeding, within 3 hours ornithine decarboxylase activity increased about 7-fold
as compared to controls, whereas the rise in Sadenosylmethionine decarboxylase activity
was less pronounced (to 125% of controls). These changes were accompanied by a normalization
of the levels of putrescine and spermidine. Interestingly, hepatic spermidine and
RNA contents fluctuated concomitantly. DNA and spermine levels, however, remained
almost unchanged during starvation and refeeding periods.
Key words
Rat Liver - Starvation - Refeeding - Ornithine Decarboxylase - S-Adenosylmethionine
Decarboxylase - Polyamines - Putrescine - Spermidine - Spermine - Nucleic Acids
1 S. Domschke's present address: Med. Univ.Klinik Erlangen-Nürnberg, D-8520 Erlangen/Germany
2 The abbreviations used in this study are: ODC: L-ornithine decarboxylase (E.C.4.1.1.17);
SAMD: S-adenosyl-L-methionine decarboxylase (E.C. not defined); PUT: putrescine; SPD:
spermidine; SP: spermine.
