Polyamines in Trypanosoma cruzi.

Growth and polyamine content of epimastigotes of Trypanosoma cruzi were studied in the presence of precursors or inhibitors of putrescine synthesis. Arginine and agmatine turned out to be better precursors than ornithine. alpha-D-difluoromethylarginine, an inhibitor of arginine decarboxylase, inhibited cellular proliferation and decreased putrescine, spermidine and spermine contents while that of cadaverine remained unchanged. These effects were reversed both by agmatine and putrescine. alpha-D-difluoromethylornithine, an inhibitor of ornithine decarboxylase did not inhibit growth of parasites grown in a polyamine free medium. These results suggest that epimastigotes need polyamines to grow, and that the parasite are able to synthesize them mainly through the arginine decarboxylase pathway.