Effect of fasting on hepatic lipase activity in the liver of developing rats

The effect of fasting on hepatic lipase was studied during postnatal develo pment in the rat, It was found that fasting produced a significant decrease in hepatic lipase only in neonatal (1-day-old) and adult (60-day-old) rats , We studied the effect of fasting on the distribution of hepatic lipase be tween extracellular (heparin-releasable) and intracellular (liver-retained or residual) compartments in perfused livers, and on the secretion of hepat ic lipase by isolated hepatocytes. Fasting had similar effects in neonates and adults: it decreased both the heparin-releasing and the residual activi ties in perfused livers, and also decreased the rate of hepatic lipase secr etion by isolated hepatocytes. Finally, the effect of fasting on hepatic li pase mRNA relative abundance in developing rat livers was determined, No di fference was observed among the groups studied, It is concluded that the me chanisms involved in the effect of fasting on hepatic lipase appear to be s imilar in neonates and adult animals and may involve the post-translational processing of the enzyme. Copyright (C) 2000 S. Karger AG, Basel.