PROTEINS BUT NOT AMINO-ACIDS, CARBOHYDRATES, OR FATS STIMULATE CHOLECYSTOKININ SECRETION IN THE RAT
PROTEINS BUT NOT AMINO-ACIDS, CARBOHYDRATES, OR FATS STIMULATE CHOLECYSTOKININ SECRETION IN THE RAT
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DOI：
10.1152/ajpgi.1986.251.2.g243
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发表时间：
1986-08-01
影响因子：
--
通讯作者：
WILLIAMS, JA
中科院分区：
文献类型：
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作者：
LIDDLE, RA;GREEN, GM;WILLIAMS, JA
由于先前测量血浆胆囊收缩素 (CCK) 水平存在困难，因此尚未确定哪些食物成分会刺激大鼠的 CCK 分泌。在本研究中，我们使用灵敏且特异的生物测定法来测量血浆 CCK，并确定了蛋白质、蛋白质水解产物、氨基酸、脂肪、淀粉和葡萄糖对该物种 CCK 分泌的影响。完整的蛋白质是 CCK 释放的唯一刺激物。 18% 酪蛋白和 0.2% 大豆胰蛋白酶抑制剂溶液导致血浆 CCK 水平从 0.5.+- 迅速增加。 0.2 至 7.9.+-。 1.9 和 8.0.+-。分别为 2.0 pM，在口胃给药后 5 分钟内。乳白蛋白和牛血清白蛋白导致循环 CCK 的升高较小。相反，酪蛋白和乳清蛋白以及氨基酸L-苯丙氨酸和L-色氨酸的水解产物不会刺激CCK释放。此外，血浆CCK水平不会随着脂肪、淀粉或葡萄糖的摄入而增加。蛋白质刺激 CCK 分泌的能力与其在体外抑制胰蛋白酶活性的能力平行。此外，同时给予胰蛋白酶可完全消除血浆CCK对酪蛋白的反应。这些研究表明蛋白质是大鼠 CCK 释放的主要食物刺激剂，并且蛋白质的作用与抑制腔内蛋白酶活性有关。
Because of prior difficulties in measuring plasma cholecystokinin (CCK) levels, it has not been established which components of food stimulate CCK secretion in rats. In the present study, we used a sensitive and specific bioassay for measuring plasma CCK and determined the effects of proteins, protein hydrolysates, amino acids, fats, starch, and glucose on CCK secretion in this species. Intact proteins were the only stimulants of CCK release. Solutions of 18% casein and 0.2% soybean trypsin inhibitor caused prompt increases in plasma CCK levels from 0.5 .+-. 0.2 to 7.9 .+-. 1.9 and 8.0 .+-. 2.0 pM, respectively, within 5 min of orogastric administration. The proteins lactalbumin and bovine serum albumin caused smaller elevations in circulating CCK. In contrast, hydrolysates of casein and lactalbumin and the amino acids L-phenylalanine and L-tryptophan did not stimulate CCK release. In addition, plasma CCK levels did not increase with the feeding of fat, starch, or glucose. The ability of proteins to stimulate CCK secretion paralleled their ability to inhibit trypsin acivity in vitro. Furthermore, the plasma CCK response to casein was completely abolished by the simultaneous administration of trypsin. These studies indicate that proteins are the major food stimulants of CCK release in the rat and that the effects of proteins are related to inhibition of intraluminal protease activity.