Abstract
Chondrocytes enzymaticaly extracted from the resting zone of GP cartilage from prepubertal rabbits, were incubated in 10% FCS-Dulbecco's medium for 48 h.They were then grown for 20 days in serum-free defined medium containing 100 ng/ml FGF as unique growth factor. Chondrocytes differentiation was observed at day 10 to 12 when cells were dividing as multilayered colonies and at day 15 to 20 when cells hypertrophied and developped important Golgi apparatus and extracellular matrix as observed by electron microscopy. At both stages of differentiation, Type II collagen was representing 95% of the newly synthesized collagenic proteins as measured after incorporation of [3H]-Pro during 20 h. The specific binding of 125I-IGFI (gift of Dr L. Van den Brande) was studied separately on dividing and hypertrophic Chondrocytes. The 50% displacement was the same at both stages of differentiation at 4.5×10−9 concentration of unlabelled IGFI. The presence of several types of receptors was suggested by Scatchard analyses with similar high affinity constant (Ka=3.3×109M−1) in dividing and hypertrophic Chondrocytes. By contrast in dividing cells the maximal specific binding observed at 15°C and pH 8 was 3 times higher than in hypertrophic cells (6% and 2% respectively) and the number of specific binding sites was 1.5 times higher than in hypertrophic cells. These results suggest that GP resting Chondrocytes can divide and hypertrophy in culture while they synthesize Type II collagen and possess a number of IGFI receptors which was decreasing during the differentiation process.
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Bourguignon, J., Bonaventure, J., de La Tour, B. et al. CHARACTERIZATION OF IGFI RECEPTORS ON IN VITRO DIFFERENTIATING GROWTH PLATE (GP) CHONDROCYTES GROWN IN CULTURE. Pediatr Res 20, 1191 (1986). https://doi.org/10.1203/00006450-198611000-00107
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DOI: https://doi.org/10.1203/00006450-198611000-00107