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<p>Despite considerable research on the differential metabolic effects of diets, information regarding the dietary energy partition process remains scarce and controversial, complicating the analysis of its main metabolic regulatory factors, including diet composition. We utilized a highly controlled dietary setup to analyze relative changes in nutrient content, measuring 17β-estradiol (E2) and testosterone (T) levels. This study integrates recalculated data from previous homologous publications with new, unpublished material, completing a multi-year investigation. We used a common chow-based model: ST or standard diet, HF high-fat and HP or high-protein. A CF, cafeteria-type diet was added for comparison. Rats (female and male) were fed the diets for 30&#xa0;d. Nutrient intake and body composition were measured. Plasma glucose, lactate, T and E2 were also measured. The energy intake of non-CF groups, was largely based in carbohydrates (CH), yielding hexoses (6C units), which were fully oxidized, or accrued as 2C fragments (via their aggregation as fatty acids). 3C glycolytic units were eventually stored, in part, as glycerol in TAG (triacyl-glycerols). In 30 d, accrual of 2C exceeded about ten-fold that of 3C. Amino acid (AA) catabolism primarily yielded 2C, 3C, and 4C–5C fragments; the latter, potentially acting as Krebs cycle anaplerotic intermediates (KCAI), facilitated 2C oxidation and reduced TAG accumulation. Lactate levels correlated with lactate dehydrogenase activities in muscle and liver. TAG accrual was maximal in CF, quite differently from HF despite having a similar dietary lipid intake proportion. Maximal rates of lipid storage were observed in the ST (and CF) groups. Females showed a higher ability to oxidize CH and to store less TAG. T was correlated with protein deposition, whilst E2 decreased this by favoring AA oxidation and raising the availability of KCAI. Results in rats suggest that an effective partition scheme requires nearly half of the energy from carbohydrates (polysaccharides). Furthermore, initial protein oxidation, yielding KCAI, facilitates 2C oxidation from carbohydrates, thereby reducing their conversion to TAG storage.</p>

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A new experimental model for the analysis of nutrient interactions on energy partition: application to the modulation of liver energy partition by dietary protein and 17β-estradiol in rats

  • 期刊论文

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  • 发表日期：

    2025年8月23日

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  • Xavier Remesar,
  • Laia Oliva,
  • José-Antonio Fernández-López,
  • Marià Alemany

摘要

Despite considerable research on the differential metabolic effects of diets, information regarding the dietary energy partition process remains scarce and controversial, complicating the analysis of its main metabolic regulatory factors, including diet composition. We utilized a highly controlled dietary setup to analyze relative changes in nutrient content, measuring 17β-estradiol (E2) and testosterone (T) levels. This study integrates recalculated data from previous homologous publications with new, unpublished material, completing a multi-year investigation. We used a common chow-based model: ST or standard diet, HF high-fat and HP or high-protein. A CF, cafeteria-type diet was added for comparison. Rats (female and male) were fed the diets for 30 d. Nutrient intake and body composition were measured. Plasma glucose, lactate, T and E2 were also measured. The energy intake of non-CF groups, was largely based in carbohydrates (CH), yielding hexoses (6C units), which were fully oxidized, or accrued as 2C fragments (via their aggregation as fatty acids). 3C glycolytic units were eventually stored, in part, as glycerol in TAG (triacyl-glycerols). In 30 d, accrual of 2C exceeded about ten-fold that of 3C. Amino acid (AA) catabolism primarily yielded 2C, 3C, and 4C–5C fragments; the latter, potentially acting as Krebs cycle anaplerotic intermediates (KCAI), facilitated 2C oxidation and reduced TAG accumulation. Lactate levels correlated with lactate dehydrogenase activities in muscle and liver. TAG accrual was maximal in CF, quite differently from HF despite having a similar dietary lipid intake proportion. Maximal rates of lipid storage were observed in the ST (and CF) groups. Females showed a higher ability to oxidize CH and to store less TAG. T was correlated with protein deposition, whilst E2 decreased this by favoring AA oxidation and raising the availability of KCAI. Results in rats suggest that an effective partition scheme requires nearly half of the energy from carbohydrates (polysaccharides). Furthermore, initial protein oxidation, yielding KCAI, facilitates 2C oxidation from carbohydrates, thereby reducing their conversion to TAG storage.