Lack of hepatic enzymatic adaptation to low and high levels of dietary protein in the adult cat.
The activities of three urea cycle enzymes, several nitrogen catabolic, gluconeogenic, and lipogenic enzymes were measured in the liver of adult cats fed: a commercial kibble; a 17.5 or 70% protein purified diet, or starved for 5 days. Except for an increase in tyrosine transaminase (EC 2.6.1.5) after feeding the high protein diet, there were no changes in the activities of the hepatic enzymes as influenced by dietary protein level. Likewise, starvation had a minimal effect on the activities of these enzymes as compared to that found in similar experiments in rats. These results indicate that the cat may have only minimal capabilities for enzyme adaptation as compared to that found in many herbivores and omnivores and may provide an explanation as to why cats have an unusually high protein requirement as compared to many other mammals.
D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D002415:Cats; D004044:Dietary Proteins; D006597:Fructose-Bisphosphatase / Q000378:metabolism; D005943:Gluconeogenesis; D005956:Glucose-6-Phosphate Isomerase / Q000378:metabolism; D006638:Histidine Ammonia-Lyase / Q000378:metabolism; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D012695:L-Serine Dehydratase / Q000378:metabolism; D008099:Liver / Q000201:enzymology*; D010729:Phosphoenolpyruvate Carboxykinase (GTP) / Q000378:metabolism; D011488:Protein Deficiency / Q000378:metabolism; D011770:Pyruvate Kinase / Q000378:metabolism; D013217:Starvation; D013913:Threonine Dehydratase / Q000378:metabolism; D014444:Tyrosine Transaminase / Q000378:metabolism
D000596:Amino Acids; D004044:Dietary Proteins; D007770:L-Lactate Dehydrogenase; D014444:Tyrosine Transaminase; D011770:Pyruvate Kinase; D006597:Fructose-Bisphosphatase; D010729:Phosphoenolpyruvate Carboxykinase (GTP); D012695:L-Serine Dehydratase; D013913:Threonine Dehydratase; D006638:Histidine Ammonia-Lyase; D005956:Glucose-6-Phosphate Isomerase