Inhibition of the enzymatic activity of PKCs reduced the incidence of S-phase entry induced by rhGGF2. The PKC inhibitor calphostin C (Cal) at 0.1, 0.5, and 1 μm in the presence of rhGGF2 reduced S-phase entry by 70% compared with the level induced in the presence of rhGGF2 alone. The PKC inhibitor BIM at 0.1, 1, and 2 μm in the presence of rhGGF2 also produced dose-dependent reductions in S-phase entry compared with the level induced in rhGGF2 alone. Each bar in Figures5-8 represents data from 20 to 37 pieces of epithelium.