Fig. 6. Fluorometric quantitation of macropinocytosis. Macrophages were pretreated with 0.1% dimethyl sulfoxide (Control), 50 µM LY294002 (LY294), 100 nM wortmannin (Wort), 10 µM ML-7 or 10 µM cytochalasin D (CyD) for 15 minutes, and incubated with 1.0 mg ml^-1 FDx150 in RB medium for 30 minutes to allow macropinocytosis. The fluorescence of cell lysates was assayed by spectrofluorometry. The values represent the mean plus or minus the standard deviation of triplicate determinations. Similar results were obtained in two additional experiments.