[Activity of gluconeogenetic enzymes in the kidney of pigs during pre- and post-natal development]

In pig fetuses (19 of 8 dams) developed by Caesarean section the dry matter and protein content of the kidneys and their PEPCK activity remain constant during the last third (from 80th to 112th day) of gestation. After birth the dry matter content of the kidneys rises slowly, but their protein content remarkably. In the kidneys of suckling piglets (17 animals of 3 offsprings) the FDPase activity remains at the same level from birth to the 9th day of life, while in the same time the G6Pase activity rises 1.5-2 times. In the kidneys of newborn piglets the total PEPCK activity increases 3-4 times and the activity of the cytosolic enzyme 2-3 times during the first 12 hours of life. At the end of the first week of life the total PEPCK activity decreases by one-third, while the activity of the cytosolic enzyme remains stable. In the kidneys of slaughter pigs (n = 7) the dry matter content and the FDPase activity are significantly higher, the protein content and the G6Pase activity are the same as in the kidneys of piglets. The total PEPCK activity is one-half, the activity of the cytosolic enzyme one-third lower than in the kidneys of piglets. In the kidneys of adult pigs the PEPCK activity is localized to equal parts in the cytosol and in the mitochondria, but in some development stages the mitochondrial part exceeds that of the cytosol. In adult pigs the PEPCK activity of the renal cortex is 2.5-3 times higher than that of the renal medulla.