The regulations of renal ammoniagenesis in the rat by extracellular factors. I. The combined effects of acidosis and physiologic fuels

Substrate oxidation by rat kidney slices regulates renal ammoniagenesis from glutamine. At concentrations close to those expected in plasma, lactate alone, or combined with other renal fuels, inhibits ammoniagenesis markedly; glucose and citrate decrease ammoniagenesis slightly. However, lactate, ci...

Full description

Saved in:
Bibliographic Details
Published inMetabolism, clinical and experimental Vol. 27; no. 11; p. 1626
Main Authors Preuss, H G, Eastman, S T, Vavatsi-Manos, O, Baird, K, Roxe, D M
Format Journal Article
LanguageEnglish
Published United States 01.11.1978
Subjects
Acidosis - metabolism
Ammonia - metabolism
Animals
Glucose - metabolism
Glutamates - metabolism
Glutamine - metabolism
Hydrogen-Ion Concentration
In Vitro Techniques
Kidney - drug effects
Kidney - metabolism
Lactates - metabolism
Lactates - pharmacology
Male
Models, Biological
Palmitates - metabolism
Rats
Starvation
Online AccessGet more information

Cover

More Information
Summary:Substrate oxidation by rat kidney slices regulates renal ammoniagenesis from glutamine. At concentrations close to those expected in plasma, lactate alone, or combined with other renal fuels, inhibits ammoniagenesis markedly; glucose and citrate decrease ammoniagenesis slightly. However, lactate, citrate, and glucose inhibit ammoniagenesis of kidney slices from acidotic rats less than ammoniagenesis of kidney slices from control rats. Lesser inhibition of ammoniagenesis is seen also when acidotic slices rather than control slices are incubated in the presence of all the tested substrates combined in the same medium. In addition to decreasing the ammoniagenesis of renal slices from control rats, the presence of lactate causes an augmented accumulation of glutamate. In contrast, adding lactate to acidotic slices does not increase glutamate accumulation nearly as much. When glutamate is substituted for glutamine in the medium, lactate still decreases ammonia production, but to a lesser extent with acidotic slices. Changes in medium pH from 7.0 to 7.8 have no, or only small, overall effects on net renal slice ammonia production from glutamine under any of the circumstances tested. We conclude that lactate alone and combined with other substrates decreases ammoniagenesis primarily at the glutamate dehydrogenase step and that slices from acidotic rats are relatively resistant to substrate mediated inhibition.
ISSN:0026-0495