Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia.
Am J Physiol Regul Integr Comp Physiol. 2020 Apr 1;318(4):R790-R798. doi: 10.1152/ajpregu.00352.2019. Epub 2020 Mar 11.
The fatty acid, lauric acid (C12), and the amino acid, leucine (Leu) stimulate gut hormones, including CCK, associated with suppression of energy intake. In our recent study, intraduodenal infusion of a combination of C12 and l-tryptophan, at loads that individually did not affect energy intake, reduced energy intake substantially, associated with much greater stimulation of CCK. We have now investigated whether combined administration of C12 and Leu would enhance the intake-suppressant effects of each nutrient, when given at loads that each suppress energy intake individually. Sixteen healthy, lean males (age: 23 ± 2 yr) received, in randomized, double-blind fashion, 90-min intraduodenal infusions of control (saline), C12 (0.4 kcal/min), Leu (0.45 kcal/min), or C12+Leu (0.85 kcal/min). Antropyloroduodenal pressures were measured continuously and plasma CCK at 15-min intervals, and energy intake from a standardized buffet-meal, consumed immediately postinfusion, was quantified. All nutrient infusions stimulated plasma CCK compared with control ( < 0.05). Moreover, C12 and C12+Leu stimulated CCK compared with Leu ( < 0.05) (mean concentration, pmol/L; control: 2.3 ± 0.3, C12: 3.8 ± 0.3, Leu: 2.7 ± 0.3, and C12+Leu: 4.0 ± 0.4). C12+Leu, but not C12 or Leu, stimulated pyloric pressures ( < 0.05). C12+Leu and C12 reduced energy intake ( < 0.05), and there was a trend for Leu to reduce ( = 0.06) energy intake compared with control, with no differences between the three nutrient treatments (kcal; control: 1398 ± 84, C12: 1226 ± 80, Leu: 1260 ± 92, and C12+Leu: 1208 ± 83). In conclusion, combination of C12 and Leu, at the loads given, did not reduce energy intake beyond their individual effects, possibly because maximal effects had been evoked.
脂肪酸月桂酸（C12）和氨基酸亮氨酸（Leu）可刺激与抑制能量摄入相关的肠道激素，包括 CCK。在我们最近的研究中，十二指肠内输注 C12 和 l-色氨酸的混合物，在单独使用时不会影响能量摄入的负荷下，可显著减少能量摄入，同时更显著地刺激 CCK 释放。我们现在研究了当以单独摄入每种营养素都能抑制能量摄入的负荷给予 C12 和 Leu 的混合物时，它们是否会增强每种营养素的摄入抑制作用。16 名健康、瘦的男性（年龄：23 ± 2 岁）以随机、双盲的方式接受 90 分钟的十二指肠内生理盐水（对照）、C12（0.4 千卡/分钟）、Leu（0.45 千卡/分钟）或 C12+Leu（0.85 千卡/分钟）输注。连续测量幽门十二指肠压力，每隔 15 分钟测量一次血浆 CCK，并在输注后立即通过标准化的自助餐定量摄入的能量。与对照相比，所有营养素输注均刺激血浆 CCK（<0.05）。此外，与 Leu 相比，C12 和 C12+Leu 刺激 CCK（<0.05）（平均浓度，pmol/L；对照：2.3 ± 0.3，C12：3.8 ± 0.3，Leu：2.7 ± 0.3，C12+Leu：4.0 ± 0.4）。C12+Leu，但不是 C12 或 Leu，刺激幽门压力（<0.05）。C12+Leu 和 C12 减少能量摄入（<0.05），Leu 有减少能量摄入的趋势（=0.06）与对照相比，三种营养素处理之间没有差异（千卡；对照：1398 ± 84，C12：1226 ± 80，Leu：1260 ± 92，C12+Leu：1208 ± 83）。总之，在给予的负荷下，C12 和 Leu 的组合并没有使能量摄入减少超过它们的单独作用，可能是因为已经引起了最大的作用。
