Effects of IGF-I, rGH, FGF, EGF and NCS on DNA-synthesis, cell proliferation and morphology of chondrocytes isolated from rat rib growth cartilage.

The effects of IGF-I, rGH, FGF, EGF and NCS on DNA-synthesis were analyzed in resting, proliferative and hypertrophic chondrocytes obtained by fractionation. Proliferation and morphology were studied on non-fractionated cells. The highest stimulation of DNA-synthesis was induced by NCS followed by IGF-I at all stages of chondrocyte differentiation. DNA-synthesis was also stimulated by a low concentration of FGF (1 microgram/1) in proliferative and hypertrophic chondrocytes, while FGF in a higher concentration (10 micrograms/1) had no significant mitogenic effect. Cell proliferation was stimulated by both NCS and IGF-I, whereas FGF and EGF only caused morphological changes. Our data indicate that IGF-I is the main serum growth factor regulating growth and proliferation by interacting with chondrocytes at all stages of differentiation.