Changes in the activities of the enzymes of hepatic ketogenesis in the rat between late fetal life and weaning.

The activities of hydroxymethylglutaryl-CoA synthase and hydroxymethylglutaryl-CoA lyase have been determined in the mitochondria and cytosol of the liver during development of the rat. Both mitochondrial enzymes exhibit similar developmental patterns with rapid rises in activity after birth, peaks of activity during early and late suckling and a trough during the mid-suckling period and a slight fall in activity (to the adult values) after weaning. Both cytosolic enzymes have low activities at all ages studied and exhibit no major developmental changes.