Resolution of soluble cyclic nucleotide phosphodiesterase isoenzymes, from liver and hepatocytes, identifies a novel IBMX-insensitive form

Concanavalin A stimulates the Rolipram-sensitive isoforms of cyclic nucleotide phosphodiesterase in rat thymic lymphocytes

Pretreatment of rat thymic lymphocytes with Concanavalin A induced a very early (30 min) and substantial increase (+90%) of the soluble cAMP phosphodiesterase activity. The crude cytosolic phosphodiesterase activity of rat thymocytes could reproducively be resolved by Mono-Q ion exchange high performance liquid chromatography into four separate phosphodiesterase peaks: a cGMP-stimulated, two cAMP-specific Rolipram-sensitive and a cGMP-inhibited cardiotrope-sensitive peaks. Concanavalin A stimulated very specifically the activity of the two predominant cAMP-specific Rolipram sensitive peaks whereas it only slightly modified the cGMP-stimulated and the cGMP-inhibited forms. The present results strongly suggest that the Rolipram-sensitive cAMP PDE activity may play a key role in the control and regulation of mitogen-induced thymocyte proliferation.