title: Adaptation to a high-protein diet progressively increases the postprandial accumulation of carbon skeletons from dietary amino acids in rats.
abstract: We aimed to determine whether oxidative pathways adapt to the overproduction of carbon skeletons resulting from the progressive activation of amino acid (AA) deamination and ureagenesis under a high-protein (HP) diet. Ninety-four male Wistar rats, of which 54 were implanted with a permanent jugular catheter, were fed a normal protein diet for 1 wk and were then switched to an HP diet for 1, 3, 6, or 14 days. On the experimental day, they were given their meal containing a mixture of 20 U-[15N]-[13C] AA, whose metabolic fate was followed for 4 h. Gastric emptying tended to be slower during the first 3 days of adaptation.15N excretion in urine increased progressively during the first 6 days, reaching 29% of ingested protein.13CO2excretion was maximal, as early as the first day, and represented only 16% of the ingested proteins. Consequently, the amount of carbon skeletons remaining in the metabolic pools 4 h after the meal ingestion progressively increased to 42% of the deaminated dietary AA after 6 days of HP diet. In contrast,13C enrichment of plasma glucose tended to increase from 1 to 14 days of the HP diet. We conclude that there is no oxidative adaptation in the early postprandial period to an excess of carbon skeletons resulting from AA deamination in HP diets. This leads to an increase in the postprandial accumulation of carbon skeletons throughout the adaptation to an HP diet, which can contribute to the sustainable satiating effect of this diet.
authors: UMR Physiologie de la Nutrition du Comportement Alimentaire, AgroParisTech, Institut National de la Recherche Agronomique, Université Paris Saclay, Paris, France.
authors: Magdalena
authors: M
authors: Stepien
authors: UMR Physiologie de la Nutrition du Comportement Alimentaire, AgroParisTech, Institut National de la Recherche Agronomique, Université Paris Saclay, Paris, France.
authors: Dalila
authors: D
authors: Azzout-Marniche
authors: UMR Physiologie de la Nutrition du Comportement Alimentaire, AgroParisTech, Institut National de la Recherche Agronomique, Université Paris Saclay, Paris, France.
authors: Patrick C
authors: PC
authors: Even
authors: UMR Physiologie de la Nutrition du Comportement Alimentaire, AgroParisTech, Institut National de la Recherche Agronomique, Université Paris Saclay, Paris, France.
authors: Nadezda
authors: N
authors: Khodorova
authors: UMR Physiologie de la Nutrition du Comportement Alimentaire, AgroParisTech, Institut National de la Recherche Agronomique, Université Paris Saclay, Paris, France.
authors: Gilles
authors: G
authors: Fromentin
authors: UMR Physiologie de la Nutrition du Comportement Alimentaire, AgroParisTech, Institut National de la Recherche Agronomique, Université Paris Saclay, Paris, France.
authors: Daniel
authors: D
authors: Tomé
authors: UMR Physiologie de la Nutrition du Comportement Alimentaire, AgroParisTech, Institut National de la Recherche Agronomique, Université Paris Saclay, Paris, France Claire.Gaudichon@agroparistech.fr.
authors: Claire
authors: C
authors: Gaudichon
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D000284:Administration, Oral; D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D002244:Carbon / Q000378:metabolism*; D004044:Dietary Proteins / Q000378:metabolism*; D005746:Gastric Emptying / Q000502:physiology; D008297:Male; D019518:Postprandial Period / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D014554:Urination / Q000502:physiology
chemical_list: D000596:Amino Acids; D004044:Dietary Proteins; D002244:Carbon
keywords: deamination; dietary amino acids; glycogen; oxidation; stable isotopes