Dataset for: Comparative effects of intraduodenal amino acid infusions on food intake and gut hormone release in healthy males

Background: In contrast to the many studies of the effects of individual amino acids (AAs) on eating, no studies have compared the effects of different AAs on eating and underlying preabsorptive gastrointestinal mechanisms. Objective: To compare the effects of intraduodenal infusions of L-tryptophan (TRP), L-leucine (LEU), L-phenylalanine (PHE) and L-glutamine (GLN) on appetite, gastrointestinal hormone responses (including ghrelin, cholecystokinin (CCK), peptide YY (PYY) and glucagon-like peptide-1 (GLP-1)), glycemia (glucagon, insulin and glucose) and test meal size in healthy males. Design: We retrospectively analyzed data from four published independent, randomized, double-blind, placebo-controlled studies of 90-min intraduodenal infusions of the individual AAs. The designs of the studies were identical, except the dose of TRP (0.15 kcal/min) was lower than that of the other AAs (0.45 kcal/min) because higher doses of this AA were not well tolerated. Results: TRP and LEU decreased intake more than PHE (reductions relative to control, ~219±68, ~170±48 and ~12±57 kcal, respectively), and TRP decreased intake more than GLN (~31±82 kcal). These effects of TRP and LEU vs. GLN, but not vs. PHE, were paralleled by greater decreases in plasma ghrelin, and increases in CCK, concentrations. TRP increased PYY more than GLN or LEU, but not PHE. LEU increased PYY less than PHE. No significant differences were detected for GLP-1. PHE increased glucagon more than TRP or LEU, and increased insulin more than TRP. Conclusion: Under our experimental conditions, intraduodenal TRP and LEU were more satiating than PHE and GLN. The greater satiating efficacy of LEU vs. PHE was significantly dissociated from the effects of these AAs on PYY, while the greater satiating potency of TRP vs. PHE was significantly dissociated from the effects of these AAs on insulin and glucagon. In contrast, ghrelin and CCK, and potentially other mechanisms, including central sensing of individual AAs, appear to be stronger candidate mechanisms for the relative satiating effects obtained.

研究背景：与大量针对单一氨基酸（amino acids, AAs）对进食行为影响的研究不同，目前尚无研究比较不同氨基酸对进食及其吸收前胃肠道潜在机制的作用。研究目的：比较十二指肠内输注L-色氨酸（L-tryptophan, TRP）、L-亮氨酸（L-leucine, LEU）、L-苯丙氨酸（L-phenylalanine, PHE）及L-谷氨酰胺（L-glutamine, GLN）对健康男性的食欲、胃肠道激素反应（包括饥饿素（ghrelin）、胆囊收缩素（cholecystokinin, CCK）、肽YY（peptide YY, PYY）及胰高血糖素样肽-1（glucagon-like peptide-1, GLP-1））、血糖代谢相关指标（胰高血糖素、胰岛素及葡萄糖）与试餐摄入量的影响。研究设计：我们对四项已发表的独立随机双盲安慰剂对照研究的数据进行了回顾性分析，这些研究均采用90分钟十二指肠内输注单一氨基酸的实验方案。各研究的实验设计完全一致，仅L-色氨酸（TRP）的输注剂量（0.15 kcal/min）低于其他三种氨基酸（0.45 kcal/min），原因是该氨基酸的高剂量耐受性较差。研究结果：L-色氨酸（TRP）与L-亮氨酸（LEU）对进食量的抑制作用强于L-苯丙氨酸（PHE）（相较于对照组的进食量减少值分别约为219±68、170±48及12±57 kcal），且L-色氨酸对进食量的抑制作用强于L-谷氨酰胺（GLN）（减少值约31±82 kcal）。相较于L-谷氨酰胺，L-色氨酸与L-亮氨酸的上述抑制作用伴随血浆饥饿素水平的显著下降及胆囊收缩素（CCK）浓度的升高，但相较于L-苯丙氨酸则无此关联。L-色氨酸对肽YY（PYY）的提升作用强于L-谷氨酰胺或L-亮氨酸，但与L-苯丙氨酸无显著差异；L-亮氨酸对肽YY的提升作用弱于L-苯丙氨酸。胰高血糖素样肽-1（GLP-1）的浓度未出现显著组间差异。L-苯丙氨酸对胰高血糖素的提升作用强于L-色氨酸或L-亮氨酸，且对胰岛素的提升作用强于L-色氨酸。研究结论：在本实验条件下，十二指肠内输注L-色氨酸与L-亮氨酸的饱腹感强于L-苯丙氨酸与L-谷氨酰胺。L-亮氨酸相较于L-苯丙氨酸更强的饱腹感效应，与二者对肽YY的影响无显著关联；而L-色氨酸相较于L-苯丙氨酸更强的饱腹感效应，则与二者对胰岛素及胰高血糖素的影响无显著关联。与之相对，饥饿素、胆囊收缩素，以及潜在的其他机制（包括中枢对单一氨基酸的感知），可能是本研究中观察到的相对饱腹感效应的更有力候选机制。