The effect of potential PKC inhibitors on osteoclastic bone resorption. Mature human osteoclasts were seeded on cortical bovine bone slices, and allowed to attach for 3 hours. Hereafter, dose-responses of the following compounds: A) GF109203X, B) Hypericin, C) Ro31-8220, D) Sphingosine, E) Palmitoyl-DL-carnitine-Cl, F) HBDDE, or G) Rottlerin was added to the cells. H) Bafilomycin A1 was used as a positive control. After five days of culture calcium release was measured in the culture supernatants. AlamarBlue was used to measure the cell viability after five days of culture. The results are presented as relative inhibition compared to vehicle treated osteoclasts. The results are representative of three individual experiments performed in quadruplicates. The asterisks indicate significant differences between vehicle and inhibitor treated conditions.