The discovery of ways by which the risk of iatrogenic hypoglycemia can be reduced in people with T1D is a priority. The proposed experiments will demonstrate the impact of increased liver glycogen content on the risk of hypoglycemia in T1D and will improve our understanding of the mechanisms by which increased glycogen improves hypoglycemic counterregulation. If hypoglycemia is reduced by increased glycogen, it will focus attention on the ways in which liver glycogen levels can be normalized in people with T1D. This would be a significant step forward in the ongoing effort to reduce the risk of iatrogenic hypoglycemia in people with T1D.