The effect of potential agonist and phagocytic stimuli on the cyclic GMP concentrations in several macrophage populations

Cyclic GMP (cGMP) levels were evaluated in oil-induced and resident guinea pig peritoneal cells and alveolar wash out cells from normal and adjuvant-injected rabbits. Basal cGMP levels in these populations were similar (0.5 to 1.5 pmol/1 x 10⁷ cells) except for an adherent subset that had a 2- to 4-fold higher concentration. These cell preparations were challenged with compounds reported to raise cGMP concentrations in other cell types and with latex beads and zymosan particles. Of the pharmacologic agents tested, only N-methyl-N'-nitro-N-nitrosoguanidine and sodium nitroprusside increased cGMP concentrations manyfold. Interaction of particulate phagocytic stimuli with mononuclear phagocytic cells in suspension or following adherence was not accompanied by significant alterations in cGMP concentrations. These data do not support a critical role for cGMP in macrophage phagocytosis.