Skip to main content
NCBI home page
Biochemical Journal logoLink to Biochemical Journal
. 1989 Dec 15;264(3):837–843. doi: 10.1042/bj2640837

Benzoate stimulates glutamate release from perfused rat liver.

D Häussinger 1, T Stehle 1, J P Colombo 1
PMCID: PMC1133661  PMID: 2575901

Abstract

In isolated perfused rat liver, benzoate addition to the influent perfusate led to a dose-dependent, rapid and reversible stimulation of glutamate output from the liver. This was accompanied by a decrease in glutamate and 2-oxoglutarate tissue levels and a net K+ release from the liver; withdrawal of benzoate was followed by re-uptake of K+. Benzoate-induced glutamate efflux from the liver was not dependent on the concentration (0-1 mM) of ammonia (NH3 + NH4+) in the influent perfusate, but was significantly increased after inhibition of glutamine synthetase by methionine sulphoximine or during the metabolism of added glutamine (5 mM). Maximal rates of benzoate-stimulated glutamate efflux were 0.8-0.9 mumol/min per g, and the effect of benzoate was half-maximal (K0.5) at 0.8 mM. Similar Vmax. values of glutamate efflux were obtained with 4-methyl-2-oxopentanoate, ketomethionine (4-methylthio-2-oxobutyrate) and phenylpyruvate; their respective K0.5 values were 1.2 mM, 3.0 mM and 3.8 mM. Benzoate decreased hepatic net ammonia uptake and synthesis of both urea and glutamine from added NH4Cl. Accordingly, the benzoate-induced shift of detoxication from urea and glutamine synthesis to glutamate formation and release was accompanied by a decreased hepatic ammonia uptake. The data show that benzoate exerts profound effects on hepatic glutamate and ammonia metabolism, providing a new insight into benzoate action in the treatment of hyperammonaemic syndromes.

Full text

PDF
837

Selected References

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

  1. Bachmann C. Diagnosis of urea cycle disorders. Enzyme. 1987;38(1-4):233–241. [PubMed] [Google Scholar]
  2. Bannai S. Exchange of cystine and glutamate across plasma membrane of human fibroblasts. J Biol Chem. 1986 Feb 15;261(5):2256–2263. [PubMed] [Google Scholar]
  3. Batshaw M. L., Brusilow S., Waber L., Blom W., Brubakk A. M., Burton B. K., Cann H. M., Kerr D., Mamunes P., Matalon R. Treatment of inborn errors of urea synthesis: activation of alternative pathways of waste nitrogen synthesis and excretion. N Engl J Med. 1982 Jun 10;306(23):1387–1392. doi: 10.1056/NEJM198206103062303. [DOI] [PubMed] [Google Scholar]
  4. Batshaw M. L., Monahan P. S. Treatment of urea cycle disorders. Enzyme. 1987;38(1-4):242–250. doi: 10.1159/000469211. [DOI] [PubMed] [Google Scholar]
  5. Brusilow S. W., Valle D. L., Batshaw M. New pathways of nitrogen excretion in inborn errors of urea synthesis. Lancet. 1979 Sep 1;2(8140):452–454. doi: 10.1016/s0140-6736(79)91503-4. [DOI] [PubMed] [Google Scholar]
  6. Colombo J. P., Bachmann C., Pfister U., Gradwohl M. Mitochondrial urea cycle enzymes in rats treated with sodium benzoate. Biochem Biophys Res Commun. 1988 Mar 15;151(2):872–877. doi: 10.1016/s0006-291x(88)80362-0. [DOI] [PubMed] [Google Scholar]
  7. Colombo J. P. Urea cycle disorders, hyperammonemia and neurotransmitter changes. Enzyme. 1987;38(1-4):214–219. doi: 10.1159/000469207. [DOI] [PubMed] [Google Scholar]
  8. Hems R., Stubbs M., Krebs H. A. Restricted permeability of rat liver for glutamate and succinate. Biochem J. 1968 May;107(6):807–815. doi: 10.1042/bj1070807. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Häussinger D., Gerok W. Hepatocyte heterogeneity in glutamate uptake by isolated perfused rat liver. Eur J Biochem. 1983 Nov 2;136(2):421–425. doi: 10.1111/j.1432-1033.1983.tb07759.x. [DOI] [PubMed] [Google Scholar]
  10. Häussinger D., Gerok W. Regulation of hepatic glutamate metabolism. Role of 2-oxoacids in glutamate release from isolated perfused rat liver. Eur J Biochem. 1984 Sep 17;143(3):491–497. doi: 10.1111/j.1432-1033.1984.tb08397.x. [DOI] [PubMed] [Google Scholar]
  11. Häussinger D., Gerok W., Sies H. Regulation of flux through glutaminase and glutamine synthetase in isolated perfused rat liver. Biochim Biophys Acta. 1983 Jan 25;755(2):272–278. doi: 10.1016/0304-4165(83)90214-3. [DOI] [PubMed] [Google Scholar]
  12. Häussinger D., Stoll B., Stehle T., Gerok W. Hepatocyte heterogeneity in glutamate metabolism and bidirectional transport in perfused rat liver. Eur J Biochem. 1989 Oct 20;185(1):189–195. doi: 10.1111/j.1432-1033.1989.tb15101.x. [DOI] [PubMed] [Google Scholar]
  13. Häussinger D., Weiss L., Sies H. Activation of pyruvate dehydrogenase during metabolism of ammonium ions in hemoglobin-free perfused rat liver. Eur J Biochem. 1975 Apr 1;52(3):421–431. doi: 10.1111/j.1432-1033.1975.tb04010.x. [DOI] [PubMed] [Google Scholar]
  14. Joseph S. K., McGivan J. D. The effect of ammonium chloride and glucagon on the metabolism of glutamine in isolated liver cells from starved rats. Biochim Biophys Acta. 1978 Sep 21;543(1):16–28. doi: 10.1016/0304-4165(78)90450-6. [DOI] [PubMed] [Google Scholar]
  15. Kaiser S., Gerok W., Häussinger D. Ammonia and glutamine metabolism in human liver slices: new aspects on the pathogenesis of hyperammonaemia in chronic liver disease. Eur J Clin Invest. 1988 Oct;18(5):535–542. doi: 10.1111/j.1365-2362.1988.tb01053.x. [DOI] [PubMed] [Google Scholar]
  16. Kodama H., Kamoshita S., Motokawa Y. Treatment of hyperammonemia with sodium benzoate. J Pediatr. 1983 Sep;103(3):498–498. doi: 10.1016/s0022-3476(83)80441-7. [DOI] [PubMed] [Google Scholar]
  17. Maswoswe S. M., Cyr D. M., Griffith A. D., Tremblay G. C. The effect of sodium benzoate on ammonia toxicity in rats. Biochem Biophys Res Commun. 1986 Jul 16;138(1):369–373. doi: 10.1016/0006-291x(86)90290-1. [DOI] [PubMed] [Google Scholar]
  18. Mendenhall C. L., Rouster S., Marshall L., Weesner R. A new therapy for portal systemic encephalopathy. Am J Gastroenterol. 1986 Jul;81(7):540–543. [PubMed] [Google Scholar]
  19. O'Connor J. E., Costell M., Grisolía S. The potentiation of ammonia toxicity by sodium benzoate is prevented by L-carnitine. Biochem Biophys Res Commun. 1987 Jun 15;145(2):817–824. doi: 10.1016/0006-291x(87)91038-2. [DOI] [PubMed] [Google Scholar]
  20. O'Connor J. E., Ribelles M., Grisolia S. Potentiation of hyperammonemia by sodium benzoate in animals. A note of caution. Eur J Pediatr. 1982 Mar;138(2):186–187. doi: 10.1007/BF00441151. [DOI] [PubMed] [Google Scholar]
  21. Palekar A. G., Canas J. A., Kalbag S. S., Kim S. J., Castro-Magana M., Angulo M. A. Failure of sodium benzoate to alleviate plasma and liver ammonia in rats. Biochem Med Metab Biol. 1989 Feb;41(1):64–69. doi: 10.1016/0885-4505(89)90009-1. [DOI] [PubMed] [Google Scholar]
  22. Ross B. D., Hems R., Krebs H. A. The rate of gluconeogenesis from various precursors in the perfused rat liver. Biochem J. 1967 Mar;102(3):942–951. doi: 10.1042/bj1020942. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Sies H., Häussinger D., Grosskopf M. Mitochondrial nicotinamide nucleotide systems: ammonium chloride responses and associated metabolic transitions in hemoglobin-free perfused rat liver. Hoppe Seylers Z Physiol Chem. 1974 Mar;355(3):305–320. doi: 10.1515/bchm2.1974.355.1.305. [DOI] [PubMed] [Google Scholar]
  24. Sies H., Noack G., Halder K. H. Carbon-dioxide concentration and the distribution of monocarboxylate and H+ ions between intracellular and extracellular spaces of hemoglobin-free perfused rat liver. Eur J Biochem. 1973 Oct 5;38(2):247–258. doi: 10.1111/j.1432-1033.1973.tb03056.x. [DOI] [PubMed] [Google Scholar]
  25. Sies H. The use of perfusion of liver and other organs for the study of microsomal electron-transport and cytochrome P-450 systems. Methods Enzymol. 1978;52:48–59. doi: 10.1016/s0076-6879(78)52005-3. [DOI] [PubMed] [Google Scholar]
  26. Stoll B., Hüssinger D. Functional hepatocyte heterogeneity. Vascular 2-oxoglutarate is almost exclusively taken up by perivenous, glutamine-synthetase-containing hepatocytes. Eur J Biochem. 1989 May 15;181(3):709–716. doi: 10.1111/j.1432-1033.1989.tb14781.x. [DOI] [PubMed] [Google Scholar]
  27. Traber P. G., Chianale J., Gumucio J. J. Physiologic significance and regulation of hepatocellular heterogeneity. Gastroenterology. 1988 Oct;95(4):1130–1143. doi: 10.1016/0016-5085(88)90194-1. [DOI] [PubMed] [Google Scholar]
  28. Wendler P. A., Tremblay G. C. Hippurate synthesis and ammonia metabolism in isolated hepatocytes. Biochem Biophys Res Commun. 1982 Apr 29;105(4):1341–1346. doi: 10.1016/0006-291x(82)90934-2. [DOI] [PubMed] [Google Scholar]

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

RESOURCES