The present invention makes available methods and reagents for modulating proliferation or differentiation in a cell or tissue comprising contacting the cell with a hedgehog agonist, such as the compounds depicted in FIGS. 32 and 33. In certain embodiments, the methods and reagents may be employed to correct or inhibit an aberrant or unwanted growth state, e.g., by antagonizing a normal ptc pathway or agonizing smoothened or hedgehog activity.