Mechanisms of hypoglycemic activity of panaxans A and B,glycans of Panax ginseng roots: Effects on plasma level,secretion, sensitivity and binding of insulin in mice

Panaxan A did not affect plasma insulin levels and insulin sensitivity, whereas Panaxan B elevated the plasma insulin level and enhanced insulin sensitivity in vivo. When mice were treated with panaxan B, insulin secretion from pancreatic islets was potentiated, while direct addition of panaxan B to pancreatic islets from normal mice showed no enhancement of insulin secretion in vitro. Hypoglycemic activity of panaxan B was not inhibited by indomethacin. Panaxans A and B showed hypoglycemic activity in spontaneously diabetic mice. Insulin binding to isolated adipocytes obtained from panaxan B-treated mice was significantly increased, while direct addition of panaxan B to isolated adipocytes from normal mice elicited no increase of insulin binding. It is concluded that a part of the hypoglycemic activity of panaxan B is due to increase of the plasma insulin level and enhancement of insulin sensitivity, while that of panaxan A is attributable to other mechanisms.