Some aspects of the metabolism of chondroitin sulfate-S35 in the rat.

The use of sulfate of exogenous origin in the synthesis of chondroitin sulfate was suggested (1) and then demonstrated by the isolation of chondroitin sulfate-W from the cartilage of rats given sulfate-V6 (2, 3). Confirmatory reports have supplemented the earlier observations (4, 5). Autoradiography has been particularly effective in showing that administered sulfate-S36 is concentrated to a greater extent in regions which have a high acid mucopolysaccharide concentration (6-21) than in regions in which the concentration of such polysaccharides is low or in which they are absent. Results of experiments in which tissue cultures (22) and cartilage slices (23, 24) were used strongly suggest that the incorporation of sulfate into chondroitin sulfate is enzymatically controlled. It is likely that the reverse reaction, namely, the hydrolytic cleavage of the sulfate group from chondroitin sulfate, is similarly affected. However, the presence in mammalian tissues of an enzyme to catalyze such a reaction has not been demonstrated. The following is a report of the fate of the sulfate group of chondroitin sulfate-W when the latter is administered to rats by stomach tube or by intraperitoneal injection.