Effect of prenatal insulin and glucagon injection on the glycogen content of rat placenta and fetal liver.

The placental glycogen content per g wet weight decreases after the 16th day of gestation but remains nearly constant till the 21st day of gestation when expressed per placenta as whole organ. Injection of insulin to rat fetuses at the 21st day of gestation gives rise to hypoglycemia and an increase of the glycogen content in liver and in placenta. Intrauterine glucagon application makes fetuses hyperglycemic in consequence of a mobilization of the placental glycogen stores. Hepatic glucose production appears in later stages because of the low activity of glucose 6-phosphatase as demonstrated by the effect of glucagon on the hepatic glucose 6-phosphate concentration.