Example of a linear dose-response curve: BrdU, a thymidine analogue, is incorporated into newly synthesized DNA of replicating cells, and can be detected using anti-BrdU antibodies. Hence, it acts as a marker of cell proliferation. The dose-response curve of BrdU uptake by satellite muscle cells in response to increasing HGF shows a linear post-peak decline in BrdU-positive cells with increasing HGF. Reprinted with permission from [10], M. Yamada, et al.; Am. J. Physiol. Cell Physiol. 298, C465 (2010). © 2010, American Physiological Society.