The effect of potential PKC inhibitors on acid secretion. Human CD14+ monocytes were isolated from blood and seeded in 96 well plates and cultured in the presence of 25 ng/ml M-CSF and RANKL for 12 days. The mature human osteoclasts were incubated for 45 minutes with acridine orange alone or in combination with the following compounds: GF109203X, Hypericin, Ro31-8220, Sphingosine, Palmitoyl-DL-carnitine-Cl, HBDDE or Bafilomycin A1 (200 nM) as a positive control. All the results are presented as % of Bafilomycin. A) Acridine Orange pictures showing the effect of the inhibitors. B) Acridine Orange readings of the green wavelength (Excitation 492 nm - emission 535 nm) was measured using a SpectraMax M5 showing the effect of the inhibitors. The results are representative of three individual experiments performed in quadruplicates. The asterisks indicate significant differences between vehicle and inhibitor treated conditions.