THE EFFECT OF OXYGEN-TENSION ON PROTEOGLYCAN SYNTHESIS AND AGGREGATION IN MAMMALIAN GROWTH PLATE CHONDROCYTES

Growth plate chondrocytes isolated from the proliferative and hypertrophic zones of bovine costochondral junctions were grown in vitro in the presence of various oxygen tensions ranging from 3 to 60%. Using [S-35] sulfate as an index of glycosaminoglycan synthesis, incorporation was found to be maximal at 21% O2. In contrast, proteoglycan aggregation under the same conditions was found to be maximal at 3% O2. There were no consistent differences in response between cells from the different morphologic zones even though they are exposed to different oxygen tensions in situ. These results show that proteoglycan synthesis and aggregation in growth plate chondrocytes in vitro are differentially affected by the ambient oxygen environment.