The effect of potential PKC inhibitors on acid influx. Acid influx in microsomes isolated from human mature osteoclasts was investigated using the dye acridine orange as described in the materials and methods section. All compounds were tested in a dose-response. A) GF109203X, B) Hypericin, C) Ro31-8220, D) Sphingosine, E) Palmitoyl-DL-carnitine-Cl, F) HBDDE, G) Rottlerin or H) Bafilomycin A1. The results are representative of three individual experiments performed in quadruplicates. The asterisks indicate significant differences between vehicle and inhibitor treated conditions.