Effect of glycyrrhizin on stability of lysosomes in the rat arterial wall.

Studies were made on the effect of phospholipase A2 on the stability of arterial wall lysosomes, and the influence of glycyrrhizin on this effect. Lysosomal phospholipase A2 activity was found to be increased in the aorta of hypercholesterolemic rats. Treatment of the lysosomal fraction of the arterial wall with venom phospholipase A2 resulted in release of acid phosphatase, and addition of glycyrrhizin (0.1 mM) inhibited this release. Lysosomal phospholipase A2 in the arterial wall was also inhibited dose-dependently by glycyrrhizin. These results suggest that lysis of lysosomes was due to increase in phospholipase A2 activity, and that glycyrrhizin stabilized the lysosomes by inhibiting phospholipase A2 activity.