The food energy/protein ratio regulates the rat urea cycle but not total nitrogen losses.

Nitrogen balance studies have shown that a portion of the N ingested but not excreted is not accounted for. We compared several diets (standard, high-fat, high-protein, and self-selected cafeteria) to determine how diet-dependent energy sources affect nitrogen handling, i.e., the liver urea cycle. D...

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Detalles Bibliográficos
Autores: Oliva Lorenzo, Laia, Alemany, Marià, 1946-, Remesar Betlloch, Xavier, Fernández López, José Antonio
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2019
País:España
Institución:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
Repositorio:Recercat. Dipósit de la Recerca de Catalunya
OAI Identifier:oai:recercat.cat:2445/127983
Acceso en línea:https://hdl.handle.net/2445/127983
Access Level:acceso abierto
Palabra clave:Urea
Rates (Animals de laboratori)
Alimentació
Nitrogen
Rats as laboratory animals
Diet
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spelling The food energy/protein ratio regulates the rat urea cycle but not total nitrogen losses.Oliva Lorenzo, LaiaAlemany, Marià, 1946-Remesar Betlloch, XavierFernández López, José AntonioUreaRates (Animals de laboratori)AlimentacióNitrogenUreaRats as laboratory animalsDietNitrogenNitrogen balance studies have shown that a portion of the N ingested but not excreted is not accounted for. We compared several diets (standard, high-fat, high-protein, and self-selected cafeteria) to determine how diet-dependent energy sources affect nitrogen handling, i.e., the liver urea cycle. Diet components and rat homogenates were used for nitrogen, lipid, and energy nalyses. Plasma urea and individual amino acids, as well as liver urea cycle enzyme activities, were determined. Despite ample differences in N intake, circulating amino acids remained practically unchanged in contrast to marked changes in plasma urea. The finding of significant correlations between circulating urea and arginine-succinate synthase and lyase activities supported their regulatory role of urea synthesis, the main N excretion pathway. The cycle operation also correlated with the food protein/energy ratio, in contraposition to total nitrogen losses and estimated balance essentially independent of dietary energy load. The different regulation mechanisms observed have potentially important nutritional consequences, hinting at nitrogen disposal mechanisms able to eliminate excess nitrogen under conditions of high availability of both energy and proteins. Their operation reduces urea synthesis to allow for a safe (albeit unknown) mechanism of N/energy excess accommodation.MDPI2019201920192019info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersion14 p.application/pdfhttps://hdl.handle.net/2445/127983Articles publicats en revistes (Bioquímica i Biomedicina Molecular)reponame:Recercat. Dipósit de la Recerca de Catalunyainstname:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)InglésReproducció del document publicat a: https://doi.org/10.3390/nu11020316Nutrients, 2019, vol. 11, num. 2, p. 316https://doi.org/10.3390/nu11020316cc-by (c) Oliva, Laia et al., 2019http://creativecommons.org/licenses/by/3.0/esinfo:eu-repo/semantics/openAccessoai:recercat.cat:2445/1279832026-05-29T05:05:01Z
dc.title.none.fl_str_mv The food energy/protein ratio regulates the rat urea cycle but not total nitrogen losses.
title The food energy/protein ratio regulates the rat urea cycle but not total nitrogen losses.
spellingShingle The food energy/protein ratio regulates the rat urea cycle but not total nitrogen losses.
Oliva Lorenzo, Laia
Urea
Rates (Animals de laboratori)
Alimentació
Nitrogen
Urea
Rats as laboratory animals
Diet
Nitrogen
title_short The food energy/protein ratio regulates the rat urea cycle but not total nitrogen losses.
title_full The food energy/protein ratio regulates the rat urea cycle but not total nitrogen losses.
title_fullStr The food energy/protein ratio regulates the rat urea cycle but not total nitrogen losses.
title_full_unstemmed The food energy/protein ratio regulates the rat urea cycle but not total nitrogen losses.
title_sort The food energy/protein ratio regulates the rat urea cycle but not total nitrogen losses.
dc.creator.none.fl_str_mv Oliva Lorenzo, Laia
Alemany, Marià, 1946-
Remesar Betlloch, Xavier
Fernández López, José Antonio
author Oliva Lorenzo, Laia
author_facet Oliva Lorenzo, Laia
Alemany, Marià, 1946-
Remesar Betlloch, Xavier
Fernández López, José Antonio
author_role author
author2 Alemany, Marià, 1946-
Remesar Betlloch, Xavier
Fernández López, José Antonio
author2_role author
author
author
dc.subject.none.fl_str_mv Urea
Rates (Animals de laboratori)
Alimentació
Nitrogen
Urea
Rats as laboratory animals
Diet
Nitrogen
topic Urea
Rates (Animals de laboratori)
Alimentació
Nitrogen
Urea
Rats as laboratory animals
Diet
Nitrogen
description Nitrogen balance studies have shown that a portion of the N ingested but not excreted is not accounted for. We compared several diets (standard, high-fat, high-protein, and self-selected cafeteria) to determine how diet-dependent energy sources affect nitrogen handling, i.e., the liver urea cycle. Diet components and rat homogenates were used for nitrogen, lipid, and energy nalyses. Plasma urea and individual amino acids, as well as liver urea cycle enzyme activities, were determined. Despite ample differences in N intake, circulating amino acids remained practically unchanged in contrast to marked changes in plasma urea. The finding of significant correlations between circulating urea and arginine-succinate synthase and lyase activities supported their regulatory role of urea synthesis, the main N excretion pathway. The cycle operation also correlated with the food protein/energy ratio, in contraposition to total nitrogen losses and estimated balance essentially independent of dietary energy load. The different regulation mechanisms observed have potentially important nutritional consequences, hinting at nitrogen disposal mechanisms able to eliminate excess nitrogen under conditions of high availability of both energy and proteins. Their operation reduces urea synthesis to allow for a safe (albeit unknown) mechanism of N/energy excess accommodation.
publishDate 2019
dc.date.none.fl_str_mv 2019
2019
2019
2019
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv https://hdl.handle.net/2445/127983
url https://hdl.handle.net/2445/127983
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv Reproducció del document publicat a: https://doi.org/10.3390/nu11020316
Nutrients, 2019, vol. 11, num. 2, p. 316
https://doi.org/10.3390/nu11020316
dc.rights.none.fl_str_mv cc-by (c) Oliva, Laia et al., 2019
http://creativecommons.org/licenses/by/3.0/es
info:eu-repo/semantics/openAccess
rights_invalid_str_mv cc-by (c) Oliva, Laia et al., 2019
http://creativecommons.org/licenses/by/3.0/es
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv 14 p.
application/pdf
dc.publisher.none.fl_str_mv MDPI
publisher.none.fl_str_mv MDPI
dc.source.none.fl_str_mv Articles publicats en revistes (Bioquímica i Biomedicina Molecular)
reponame:Recercat. Dipósit de la Recerca de Catalunya
instname:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
instname_str Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
reponame_str Recercat. Dipósit de la Recerca de Catalunya
collection Recercat. Dipósit de la Recerca de Catalunya
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15,812455

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