Abstract
We observed that prostuglandins (PG) E1, E2, A1, A2, B1, and F2 alpha increase cAMP concentration in resting neutrophils. In phagocytosing cells, an additional enhancement was seen with PG E1 and PG A2. Such a stimulatory effect of Pg E1 was noted any time during phagocytosis of latex microparticles (3-18 min). Adrenergic inhibitors, phentolamine and propranolol, did not interfere with the stimulatory action of PG E1 on cAMP level in resting and phagocytosing leukocytes. Both aforementioned inhibitors enhanced cAMP level in resting and phagocytosing neutrophils at 1 mM concentration, and an additional increase was seen in PG E1stimulated leukocytes. Although phosphodiesterase activity was unchanged by phagocytosis and PG E1 action, adenylate cyclase (AC) activity was significantly higher in neutrophil homogenates after phagocytosis of latex particles. In contrary, contact of human lymphocytes with latex particles revealed a decrease in AC activity. These data indicate that AC-cAMP system is partly in a restrained state in resting neutrophils and can be relieved by phagocytosis.
