Distribution profile of glucokinase and hexokinase in parenchymal and sinusoidal cells of rat liver during development

Activities of glucokinase and hexokinase were measured in whole liver, in isolated parenchymal cells and in sinusoidal cells from neonatal, suckling and weanling rats. Hexokinase activity was found to be high in fetal and newborn livers, decreased gradually and attained a plateau in 21 days. Glucokinase activity, on the other hand, was very low in fetal and newborn livers, but increased 40 fold in 21 days after birth. Measurement of the enzyme activities in isolated cells revealed a gradual increase in glucokinase activity in parenchymal cells and a parallel decrease of this enzyme in sinusoidal cells as a function of age. Hexokinase activity in parenchymal or sinusoidal cells did not change significantly at different stages of growth. The relative contribution by parenchymal cells to the liver glucokinase activity increased gradually during maturation whereas that by the sinusoidal cells decreased during this period. The evidence presented suggests that sinusoidal cells may be playing a vital role in the metabolic activities of liver in the early stages of postnatal development.