De novo synthesis of glucokinase in hepatocytes isolated from neonatal rats.

Hepatic glucokinase (EC 2.7.1.2) is first detectable around the 16th day in the neonatal rat [ l-31. Precocious appearance of the enzyme is induced by intubation of glucose; the resulting activities are enhanced by prior treatment of the animals with triiodothyronine (T3) [4,5]. The factors that regulate synthesis of glucokinase in neonatal rat liver are complex [6] and it would be advantageous to be able to study its synthesis in a liver preparation in isolation from extra-hepatic influences. We now report that rapid de novo synthesis of glucokinase can be induced in vitro by glucose plus insulin in hepatocytes isolated from 13-day-old rats. The synthesis is glucose-concentration dependent.