DURING the course of administering glucagon (hyperglycemicglycogenolytic factor) intravenously to rabbits it was found that in an occasional animal this factor produced an insignificant elevation or no rise in blood glucose. The site of the hyperglycemic action of glucagon appears to be the liver (Collens and Murlin, 1929); presumably, therefore, any factor that would increase the glycogen content of the liver should enhance the hyperglycemic effect of glucagon. It is well known that Cortisone will increase the liver glycogen stores. Since ACTH increases the glucocorticoid output of the adrenal glands, it should have a similar biological activity. Consequently, glucagon was administered intravenously to a group of rabbits before and after treatment with ACTH or with Cortisone. At the time this project was started no reports could be found in the literature showing that ACTH caused an increased in the liver-glycogen content in normal rabbits.