Development of renal gluconeogenesis in chicks fed high fat and high protein "carbohydrate-free" diets
Evans, R.M.; Scholz, R.W.
Journal of Nutrition 103(2): 242-250
1973
ISSN/ISBN: 0022-3166 PMID: 4684359 Document Number: 57415
The activities of selected liver and kidney enzymes associated with gluconeogenesis and the capacity of kidney slices to form glucose from glycerol and pyruvate were studied in developing chick embryos and in hatched chicks during adaptation to carbohydrate-free diets high in fat (HF) and high in protein (HP). Although the specific pattern of development for each enzyme differed, the activities of phosphoenolpyruvate carboxykinase (PEPCK), glycerol kinase (GK) and L-glycerol-3-phosphate dehydrogenase (GPDH) were higher in embryonic liver than kidney from 13 days of incubation to hatching. Xanthine dehydrogenase (XDH) activity was higher in embryonic kidney than liver. The activities of all 4 enzymes increased in liver and kidney of hatched chicks and reached peak values within 10 days. Chicks given the HF diet had less liver PEPCK, more kidney PEPCK, more liver and kidney GK and unchanged liver and kidney XDH activities compared with those of controls. The activities of liver and kidney PEPCK, GK and XDH were greater in chicks given the HP diet than in controls. No effect on liver or kidney GPDH activity was detected. Glucose formation from glycerol and pyruvate rose in kidney slices of chicks given the carbohydrate-free diets. The results suggest that renal gluconeogenesis from pyruvate, and hence from glucogenic amino acids, may be of greater relative significance than glucose formation from glycerol.