Effects of inhibitors on calcium deposition in cartilage in vitro.

The presence of enzymes in epiphyseal cartilage has long been recognized, but their rale in the process of calcification remains unsettled. Phosphatase (l-3), phosphorylase (4), and glycolytic activity (5,6) have been demonstrated in epiphyseal cartilage. Recent work suggests that mineralization of epiphyseal cartilage is related to the glycogen in the zone of hypertrophic cells of the epiphyseal cartilage plate (7, 8) and to phosphorylative glycolysis (6, 9). Available evidence indicates that cartilage has a low content of oxidative enzyme systems (10-12). In the accompanying paper (9), the relation of glycogen and of phosphorylative glycolysis to the deposition of bone salt in preosseous cartilage was considered. The present study was undertaken in an effort to elucidate further the nature of the process of calcification of epiphyseal cartilage in vitro, with particular attention to the r8les of oxidative systems and of alkaline phosphatase.