Studies on urea cycle enzymes in rat liver during acute uraemia.
Activities of urea cycle enzymes were measured in the liver of starved rats 12 and 48 h after bilateral nephrectomy. Control experiments (sham-operated, starved rats) revealed that the activities of only two enzymes of the cycle are altered in the uraemic state: argininosuccinic acid synthetase (EC 6.3.4.5.), which is considered to be rate limiting for urea production and carbamyl phosphate synthetase (EC 2.7.2.5.). Alterations in ornithine concentration of the liver, a possible cause of an increased urea production rate, could not be detected previously (21). Our present results do not support the concept that a decrease of the activity of ornithine-delta-amino transferase (EC 2.6.1.13), leading to an increase in the ornithine content of the liver is responsible for the accelerated urea production rate in the liver of acute uraemic rats.
D000208:Acute Disease; D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D008099:Liver / Q000201:enzymology* / Q000378:metabolism; D009952:Ornithine / Q000378:metabolism; D051381:Rats; D000637:Transaminases / Q000378:metabolism; D014508:Urea / Q000378:metabolism*; D014511:Uremia / Q000201:enzymology*
D014508:Urea; D009952:Ornithine; D000637:Transaminases