[Lactate dehydrogenase (LDH) and isoenzymes in pig liver during postnatal development]

1. LDH-activity in the liver of newborn piglets is 4 times that of adult pig sliver and remains relatively constant at this level during the first 3 weeks of life. 2. 90% of LDH is localized in the cytosolic compartment of the liver, independent of age of pigs. 3. In the liver of newborn piglets the isoenzymes LDH-3 and LDH-4 includes the main part of LDH-activity. The typical distribution of LDH isoenzymes in the liver of adult pigs (LDH-3 greater than LDH-2 greater than LDH-1 greater than LDH-4 greater than LDH-5) is already reached in 6-day-old piglets. Afterwards there follows only a decrease of LDH-1. Therefore, during postnatal development a directed shift from M- to H-type of isoenzyme distribution is observed.