Luminal peptide YY-releasing factors in the isolated vascularly perfused rat colon
Luminal peptide YY-releasing factors in the isolated vascularly perfused rat colon
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DOI：
10.1677/joe.0.1510421
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发表时间：
1996-12-01
影响因子：
4
通讯作者：
Cuber, JC
中科院分区：
文献类型：
--
作者：
Plaisancie, P;Dumoulin, V;Cuber, JC
肽YY （PYY）产生于主要定位于远端肠的内分泌L细胞。这些开放型L细胞与肠道食糜接触，从而影响其分泌活性。本研究的目的是利用分离的血管灌注大鼠结肠，检查结肠内容物中发现的各种各样的腔内化合物作为pyy释放因子的潜力。通过特定的RIA测量PW向门静脉流出物的释放。5 mM葡萄糖或0.5% （w/v）淀粉腹腔注射30分钟后，PYY的释放不明显。油酸（10和100 mM）也没有显著增加PW分泌。葡萄糖药理学浓度（250 mM）和氨基酸混合物（总浓度250 mM）均诱导PW分泌（基础浓度的200%）。果胶是一种聚半乳糖醛酸，在0.1-0.5% （w/v）范围内引起pyy样免疫反应性的剂量依赖性分泌。在0-5%的果胶输注诱导PW的快速和持续释放（基础的300%）后，观察到最大的反应。半乳糖醛酸本身（5%）产生显著的PW分泌。阿拉伯胶（0.5%）诱导门脉PW浓度逐渐增加（最大反应为基础值的250%），而纤维素（0.5%）没有引起PW分泌。在0.5- 5mm的范围内，腹腔正丁酸盐产生PYY的剂量依赖性释放（5mm正丁酸盐的最大响应是基础值的300%）。将正丁酸盐浓度增加至100 mM，可引起PW分泌逐渐减少。丙酸盐的刺激作用不如正丁酸盐，而醋酸盐对PW分泌的增加作用也不高于基础值。在浓度为2或20 mM时，牛磺胆酸盐、胆酸盐和脱氧胆酸盐均能促进PW的分泌，而脱氧胆酸盐对PW的分泌没有影响。综上所述，葡萄糖和氨基酸可能介导PW的释放，但仅当它们在结肠中以高生理浓度存在时，而油酸不产生任何PW分泌。生理浓度的纤维（果胶、阿拉伯胶）、乳木酸链脂肪酸（正丁酸盐、丙酸盐）和胆盐（牛磺酸胆酸盐、胆酸胆酸盐、脱氧胆酸胆酸盐）都是PW释放的有效刺激物。PW的释放是否通过局部/旁分泌途径与水和电解质的转移相耦合仍然是一个悬而未决的问题，这需要对离体血管灌注结肠制备进行额外的研究。
Peptide YY (PYY) is produced in endocrine L cells primarily localized in the distal bowel. These open-type L cells make contact with the intestinal chyme which may thus affect their secretory activity. The aim of the present study was to examine a large variety of luminal compounds found in colonic contents for their potential as PYY-releasing factors, using the isolated vascularly perfused rat colon. The release of PW into the portal effluent was measured by a specific RIA. Luminal administration of 5 mM glucose or 0.5% (w/v) starch for 30 min did not induce significant release of PYY. Oleic acid (10 and 100 mM) also did not significantly increase PW secretion. A pharmacological concentration of glucose (250 mM) and a mixture of amino acids (total concentration 250 mM) both induced PW secretion (200% of basal). Pectin, a polygalacturonic acid, evoked dose-dependent secretion of PYY-like immunoreactivity over the range 0.1-0.5% (w/v). The maximal response was observed after infusion of 0-5% pectin which induced a prompt and sustained release of PW (300% of basal). Galacturonic acid itself (5%) produced marked PW secretion. Gum arabic (0.5%) induced a gradual increase in portal PW concentration (maximal response 250% of the basal value) whereas cellulose (0.5%) did not elicit PW secretion. Luminal n-butyrate over the range 0.5-5 mM produced a dose-dependent release of PYY (maximal response 300% of the basal value with 5 mM n-butyrate). Increasing the concentration of n-butyrate to 100 mM provoked a gradual decrease in PW secretion. Propionate was a less potent stimulant than n-butyrate, and acetate did not increase PW secretion above the basal value. At a concentration of 2 or 20 mM, taurocholate, cholate and deoxycholate brought about PW secretion while hyodeoxycholate was without effect.In conclusion, glucose and amino acids may mediate PW release but only when they are present at high supraphysiological concentrations in the colon while oleic acid does not produce any PW secretion. Physiological concentrations of fibers (pectin, gum arabic), shea-chain fatty acids (n-butyrate, propionate) and bile salts (taurocholate, cholate, deoxycholate) are all potent stimulants of PW release. Whether the release of PW by luminal factors is coupled to water and electrolyte transfer via a local/paracrine pathway remains an open question which requires additional work with the isolated vascularly perfused colon preparation.