DEVELOPMENT OF GLUCONEOGENIC, GLYCOLYTIC, AND PENTOSE-SHUNT ENZYMES IN THE CHICKEN KIDNEY

The activities of the key gluconeogenic, glycolytic, and pentose-shunt enzymes in chicken kidney were determined starting from 8 days before to 58 days after hatching. The activities of pyruvate carboxylase (PC), mitochondrial and cytosolic phosphoenolypruvate carboxykinase (PEPCK), fructose-1,6-diphosphatase (FDPase) and glucose-6-phosphatase (G6Pase) were low in the embryonic tissue but increased towards the time of hatching. After hatching, the activities of PC, mitochondrial PEPCK, and G6Pase continued to increase, but those of FDPase and cytosolic PEPCK decreased. Relatively little change in these activities was observed in chickens over 24 days old. The activities of hexokinase (HK), phosphofructokinase (PFK), pyruvate kinase (PK), and lactate dehydrogenase (LDH) increased during embryonic growth. After hatching, HK activity continued to increase and then decrease, whereas PFK appeared to decrease and then increase to prehatch levels in 28-day-old birds. LDH activity continued to increase until 8 days after hatching and remained constant thereafter. No definite pattern was discernible in the case of PK. As for the pentose-shunt enzymes, there was no significant change in glucose-6-phosphate dehydrogenase activity (G6PDH), but the activity of 6-phosphogluconate dehydrogenase (6PGDH) increased until the chickens were 14 days old and then remained relatively constant.