Concentration-dependent effects of the soluble guanylyl cyclase inhibitor LY83583 on cGMP formation by human peripheral monocytes incubated in the presence of Lp(a) (300 μg/mL) for 2 minutes. Monocytes were pretreated with LY83583 for 15 minutes before addition of Lp(a). The incubations were stopped with ice-cold perchloric acid and by rapid cooling. After neutralization, cGMP contents were analyzed radioimmunologically. **P < .01 versus samples without LY83583. The data show mean ± SEM of four independent experiments.