Signal transduction in Trypanosoma cruzi: opposite effects of adenylcyclase and phospholipase C systems in growth control.

Fetal calf serum (FCS), which is mitogenic for the pathogenic protozoa T. cruzi, inhibits cAMP production in basal and forskolin-stimulated epimastigotes. It also activates phosphoinositides hydrolysis yielding diacylglycerol and inositol phosphates (Ins-P). Ins-P production is enhanced by AlF4-, GTP or beta-gamma-methylene-GTP, thus implying G proteins mediation in the phenomenon. An enzyme with phospholipase C activity which may be involved in the phospholipid metabolism was partially characterized.