Hormonal control of fructose 2,6-bisphosphate concentration and of phosphofructokinase 2 in the rat liver during development.

In fetal rat liver the concentration of fructose 2,6-bisphosphate is decreased by administration of glucagon. The glucagon effect, i.e., the phosphorylation state of phosphofructokinase 2, dominates over the substrate supply. Insulin was found to increase fructose 2,6-bisphosphate only when exogenous glucose is supplied simultaneously. The total activity of phosphofructokinase 2 exhibits remarkable developmental changes. It is high at term, moderate in the fetal as well as in the mature organ, and low during suckling. The level of the enzyme during development is controlled by pancreatic and adrenal hormones.