Variation in the responsiveness of myogenic satellite cell subpopulations to mitogenic stimuli was examined in cells isolated from the turkey pectoralis major muscle. Faster growing clonal cell populations were more responsive to fibroblast growth factor (FGF-2) and expressed greater levels of FGF-2 and FGF receptor-1 at the onset of proliferation than did slower growing cells. Faster growing clones also expressed higher levels of heparan sulfate proteoglycans (HSPG), especially during differentiation, than did slower growing clones. HSPG, which is important in FGF receptor signaling, increased during proliferation of all clones tested and decreased in all but one of the clones during differentiation. Slower growing clones increased their expression of FGF receptor-1 through proliferation and differentiation. However, expression of the receptor in faster growing clones decreased during differentiation. The FGF receptors-2 and -3 were not detected on turkey satellite cells or myotubes by reverse transcriptase-polymerase chain reaction methodology. These results demonstrate that there is heterogeneity in the properties and responsiveness of satellite cell populations derived from single muscles. Satellite cells that differ in proliferation rates differ in responsiveness to FGF-2, and in the expression of FGF-2, FGF receptor-1, and HSPG.