Skip to main content
PMC home page
Biochemical Journal logoLink to Biochemical Journal
. 1993 Jul 15;293(Pt 2):339–344. doi: 10.1042/bj2930339

Rapid activation of hepatic glutaminase in rats fed on a single high-protein meal.

H S Ewart 1, J T Brosnan 1
PMCID: PMC1134364  PMID: 8343112

Abstract

We report that hepatic glutaminase is rapidly activated in rats fed on a single high-protein (60% casein) meal. Rats previously fed on a normal-protein (15% casein) diet for 3-4 days were given a high-protein meal for 2 h. The high-protein meal increased the rate of flux through glutaminase in intact liver mitochondria nearly 3-fold (20.6 +/- 1.7 nmol/min per mg of protein versus 7.5 +/- 2.9 nmol/min per mg of protein) at a P(i) concentration of 10 mM. The activation of flux through glutaminase by a high-protein meal involved an increased sensitivity of glutaminase to P(i), an activator of the enzyme. The Ka for P(i) was 1.0 mM and 24.1 mM in mitochondria from rats fed on the high-protein and normal-protein meals respectively. We measured the concentration of P(i) in the mitochondrial matrix and found that it did not differ in mitochondria from rats fed on the high-protein and normal-protein meals, suggesting that the effect of the high-protein meal on the P(i)-sensitivity of glutaminase was not due to a change in the distribution of P(i) across the mitochondrial inner membrane. Glutaminase activity was measured by using mitochondrial membranes from frozen-thawed mitochondria. Glutaminase activity and its dependence on P(i) were similar for preparations from rats fed on high-protein and normal-protein meals. These findings show that hepatic glutaminase is stimulated rapidly by a high-protein meal. This is part of the physiological hepatic response to increased protein intake which permits the liver to cope with the influx of glutamine occurring at this time.

Full text

PDF
339

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Akerboom T. P., Bookelman H., Zuurendonk P. F., van der Meer R., Tager J. M. Intramitochondrial and extramitochondrial concentrations of adenine nucleotides and inorganic phosphate in isolated hepatocytes from fasted rats. Eur J Biochem. 1978 Mar 15;84(2):413–420. doi: 10.1111/j.1432-1033.1978.tb12182.x. [DOI] [PubMed] [Google Scholar]
  2. Corvera S., García-Sáinz J. A. Hormonal stimulation of mitochondrial glutaminase. Effects of vasopressin, angiotensin II, adrenaline and glucagon. Biochem J. 1983 Mar 15;210(3):957–960. doi: 10.1042/bj2100957. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Ewart H. S., Jois M., Brosnan J. T. Rapid stimulation of the hepatic glycine-cleavage system in rats fed on a single high-protein meal. Biochem J. 1992 Apr 15;283(Pt 2):441–447. doi: 10.1042/bj2830441. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Fisher M. J., Pogson C. I. Phenylalanine hydroxylase in liver cells. Correlation of glucagon-stimulated enzyme phosphorylation with expressed activity. Biochem J. 1984 Apr 1;219(1):79–85. doi: 10.1042/bj2190079. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Herzfeld A., Raper S. M. The heterogeneity of arginases in rat tissues. Biochem J. 1976 Feb 1;153(2):469–478. doi: 10.1042/bj1530469. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Jois M., Ewart H. S., Brosnan J. T. Regulation of glycine catabolism in rat liver mitochondria. Biochem J. 1992 Apr 15;283(Pt 2):435–439. doi: 10.1042/bj2830435. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Jois M., Hall B., Fewer K., Brosnan J. T. Regulation of hepatic glycine catabolism by glucagon. J Biol Chem. 1989 Feb 25;264(6):3347–3351. [PubMed] [Google Scholar]
  8. Joseph S. K., McGivan J. D. The effects of ammonium chloride and bicarbonate on the activity of glutaminase in isolated liver mitochondria. Biochem J. 1978 Dec 15;176(3):837–844. doi: 10.1042/bj1760837. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Jungas R. L., Halperin M. L., Brosnan J. T. Quantitative analysis of amino acid oxidation and related gluconeogenesis in humans. Physiol Rev. 1992 Apr;72(2):419–448. doi: 10.1152/physrev.1992.72.2.419. [DOI] [PubMed] [Google Scholar]
  10. Krebs H. A. Some aspects of the regulation of fuel supply in omnivorous animals. Adv Enzyme Regul. 1972;10:397–420. doi: 10.1016/0065-2571(72)90025-8. [DOI] [PubMed] [Google Scholar]
  11. Lacey J. H., Bradford N. M., Joseph S. K., McGivan J. D. Increased activity of phosphate-dependent glutaminase in liver mitochondria as a result of glucagon treatment of rats. Biochem J. 1981 Jan 15;194(1):29–33. doi: 10.1042/bj1940029. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. McGivan J. D., Lacey J. H., Joseph S. K. Localization and some properties of phosphate-dependent glutaminase in disrupted liver mitochondria. Biochem J. 1980 Nov 15;192(2):537–542. doi: 10.1042/bj1920537. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Meijer A. J. Channeling of ammonia from glutaminase to carbamoyl-phosphate synthetase in liver mitochondria. FEBS Lett. 1985 Oct 28;191(2):249–251. doi: 10.1016/0014-5793(85)80018-1. [DOI] [PubMed] [Google Scholar]
  14. Meijer A. J., Verhoeven A. J. Regulation of hepatic glutamine metabolism. Biochem Soc Trans. 1986 Dec;14(6):1001–1004. doi: 10.1042/bst0141001. [DOI] [PubMed] [Google Scholar]
  15. Miller R. H., Eisenstein R. S., Harper A. E. Effects of dietary protein intake on branched-chain keto acid dehydrogenase activity of the rat. Immunochemical analysis of the enzyme complex. J Biol Chem. 1988 Mar 5;263(7):3454–3461. [PubMed] [Google Scholar]
  16. Morimoto B. H., Brady J. F., Atkinson D. E. Effect of level of dietary protein on arginine-stimulated citrulline synthesis. Correlation with mitochondrial N-acetylglutamate concentrations. Biochem J. 1990 Dec 15;272(3):671–675. doi: 10.1042/bj2720671. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Rabier D., Briand P., Petit F., Parvy P., Kamoun P., Cathelineau L. Acute effects of glucagon on citrulline biosynthesis. Biochem J. 1982 Sep 15;206(3):627–631. doi: 10.1042/bj2060627. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Robinson J. L., Foustock S., Chanez M., Bois-Joyeux B., Peret J. Circadian variation of liver metabolites and amino acids in rats adapted to a high protein, carbohydrate-free diet. J Nutr. 1981 Oct;111(10):1711–1720. doi: 10.1093/jn/111.10.1711. [DOI] [PubMed] [Google Scholar]
  19. SCHIMKE R. T. Adaptive characteristics of urea cycle enzymes in the rat. J Biol Chem. 1962 Feb;237:459–468. [PubMed] [Google Scholar]
  20. Smith E. M., Watford M. Rat hepatic glutaminase: purification and immunochemical characterization. Arch Biochem Biophys. 1988 Feb 1;260(2):740–751. doi: 10.1016/0003-9861(88)90504-8. [DOI] [PubMed] [Google Scholar]
  21. Stewart P. M., Walser M. Short term regulation of ureagenesis. J Biol Chem. 1980 Jun 10;255(11):5270–5280. [PubMed] [Google Scholar]
  22. Swain R. R., Briggs S. L. Positive interference with the Jaffé reaction by cephalosporin antibiotics. Clin Chem. 1977 Jul;23(7):1340–1342. [PubMed] [Google Scholar]
  23. Szweda L. I., Atkinson D. E. Response of rat liver glutaminase to pH. Mediation by phosphate and ammonium ions. J Biol Chem. 1989 Sep 15;264(26):15357–15360. [PubMed] [Google Scholar]
  24. Vargas A. M., Halestrap A. P., Denton R. M. The effects of glucagon, phenylephrine and insulin on the phosphorylation of cytoplasmic, mitochondrial and membrane-bound proteins of intact liver cells from starved rats. Biochem J. 1982 Oct 15;208(1):221–229. doi: 10.1042/bj2080221. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Watford M., Erbelding E. J., Shapiro A. C., Zakow A. M., Smith E. M. The adaptive response of phosphate-activated glutaminase in the rat. Contrib Nephrol. 1985;47:140–144. doi: 10.1159/000411221. [DOI] [PubMed] [Google Scholar]
  26. Watford M., Smith E. M. Distribution of hepatic glutaminase activity and mRNA in perivenous and periportal rat hepatocytes. Biochem J. 1990 Apr 1;267(1):265–267. doi: 10.1042/bj2670265. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Biochemical Journal are provided here courtesy of The Biochemical Society

RESOURCES