The effect of age on glycosaminoglycan synthesis in rabbit articular and costal cartilages.

The rates of synthesis of chondroitin 4- and 6-sulfate were compared for articular and costal cartilage from rabbits of three different ages. Cartilages were labeled in vitro with 3H glucosamine and 35SO4. The glycosaminoglycans were isolated and separated and assayed for radioactivity and uronic acid content. The data obtained showed that in immature articular cartilage the rate of synthesis of chondroitin 4-sulfate is considerably greater than for chondroitin 6-sulfate and that this condition is reversed as the animal ages. These results are concordant with the known variation in distribution of the glycosaminoglycans with age and suggest that the chondrocyte alters its synthetic activity with advancing age.