Abstract
1. 1. L-Glutamine conversion into ammonia, urea and glucose by the perfused liver of 48 hr starved guinea-pigs was concentration dependent attaining the maximal rate at 4 mM. 2. 2. The activity of glutaminase I (EC 3.5.12), measured in isolated liver mitochondria was high enough to account for the observed rate of ammonia, urea and glucose formation by the perfused liver. Neither NH4C1 (5 mM) nor aminooxyacetate (0.5 mM) affected the rate of glutamine conversion into glutamate by isolated liver mitochondria. 3. 3. Gluconeogenesis and ureogenesis from glutamine was inhibited by octanoate, Dt-3-hydroxybutyrate, aminooxyacetate, ethanol and p-hydroxyphenylpyruvate while ammonia formation was stimulated by aminooxyacetate. 2,4-Dinitrophenol stimulated the rate of the formation of all three metabolites from glutamine. 4. 4. The major changes induced by aminooxyacetate, as determined in livers perfused with glutamine and stopped by freeze-clamping technique, consisted in a decrease in the content of ATP, aspartate and malate and in a slight increase in the content of glutamate. 5. 5. Glutamine is an effective precursor of phosphoenolpyruvate in isolated liver mitochondria. Its formation was inhibited by octanoate and by DL-3-hydroxybutyrate. 6. 6. The data are discussed in terms of regulation of glutamine catabolism in liver with emphasis on ureogenesis and gluconeogenesis.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
