Polyamine metabolism in prostaglandin E2-treated human T lymphocytes

The effects of Prostaglandin (PG) E2 treatment of human T lymphocytes on po lyamine metabolism were investigated. PGE2 is known to inhibit lymphocyte p roliferation, while polyamines play an important role in several biochemica l processes leading to increased cell growth. Preincubation of T lymphocyte s with PGE2 (10(-6)M) for 10 min. was able to increase ornithine decarboxyl ase (ODC) activity and putrescine as well as spermine levels, while spermid ine concentration was drastically reduced. After 30 and 60 min of treatment , a decrease in ODC activity and putrescine concentration was observed. On the contrary, the initial inhibition of spermine-N1-acetyltransferase (SAT) activity was followed by a progressive increase of this catabolic enzyme. These changes were related to modifications of cAMP concentrations. Our dat a may help clarify the mechanisms: underlying the biphasic effect of PGE2, which ultimately leads to inibition of eel proliferation.