Role of Fetal Insulin in Glycogen Metabolism in the Liver of the Rat Fetus

Abstract

In the near-term rat fetus liver, insulin decreased phosphorylase a activity, slightly increased synthase a activity and increased both glycogen content and ¹⁴C-glucose incorporation into glycogen; anti-insulin serum increased phosphorylase a activity and decreased glucose incorporation but did not modify synthase a activity. When pregnant rats were previously rendered hypoglycemic, insulin injection to the fetus enhanced glycogen accumulation. It is concluded that insulin is a regulatory factor of secondary importance for liver glycogen storage through its action on phosphorylase activity.