Friedman M I, Ramirez I, Tordoff M G
Monell Chemical Senses Center, Philadelphia, Pennsylvania 19104, USA.
Am J Physiol. 1996 Mar;270(3 Pt 2):R688-92. doi: 10.1152/ajpregu.1996.270.3.R688.
Evidence that ingested fat acts in the intestine to produce satiety stems from studies showing that intraintestinal infusion of fat emulsion inhibits eating behavior of rats. In this study, we determined the appropriateness of infusion parameters used in these behavioral studies by measuring gastric emptying rates of both the aqueous and lipid components of Intralipid ingested normally by rats. Stomach contents were collected at different times 0-40 min after rats ingested Intralipid containing [14C]polyethylene glycol (PEG) and phenol red (PR) and were assayed for PEG, PR, and fat. The proportion of ingested fat remaining in the stomach was significantly greater than the proportion of ingested PEG or PR at all time points examined. Despite initial gastric emptying of fat during ingestion, consumption of Intralipid (0.5 or 1.1 kcal/ml) did not suppress subsequent solid food intake. The results indicate that 1) ingested fat emulsion rapidly partitions in the rat stomach into an aqueous phase, which empties rapidly, and a lipid phase, which empties slowly, and 2) normal ingestion of Intralipid is not immediately satiating. These observations raise questions about the physiological significance of the rapid and marked suppression of feeding behavior produced by intraintestinal infusion of Intralipid.
摄入的脂肪在肠道中产生饱腹感的证据源于多项研究，这些研究表明，向肠道内输注脂肪乳剂会抑制大鼠的进食行为。在本研究中，我们通过测量大鼠正常摄入的英脱利匹特（Intralipid）的水性成分和脂质成分的胃排空率，来确定这些行为学研究中所使用输注参数的适宜性。在大鼠摄入含有[14C]聚乙二醇（PEG）和酚红（PR）的英脱利匹特后的0至40分钟的不同时间点收集胃内容物，并对PEG、PR和脂肪进行检测。在所有检测的时间点，胃中残留的摄入脂肪比例均显著高于摄入的PEG或PR的比例。尽管在摄入过程中脂肪最初会从胃中排空，但摄入英脱利匹特（0.5或1.1千卡/毫升）并未抑制随后的固体食物摄入量。结果表明：1）摄入的脂肪乳剂在大鼠胃中迅速分离成快速排空的水相和缓慢排空的脂质相；2）正常摄入英脱利匹特不会立即产生饱腹感。这些观察结果引发了关于肠道内输注英脱利匹特所导致的进食行为迅速且显著抑制的生理意义的疑问。
