CHOLECYSTOKININ BIOACTIVITY IN HUMAN-PLASMA - MOLECULAR-FORMS, RESPONSES TO FEEDING, AND RELATIONSHIP TO GALLBLADDER CONTRACTION
CHOLECYSTOKININ BIOACTIVITY IN HUMAN-PLASMA - MOLECULAR-FORMS, RESPONSES TO FEEDING, AND RELATIONSHIP TO GALLBLADDER CONTRACTION
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DOI：
10.1172/jci111809
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发表时间：
1985-01-01
影响因子：
15.9
通讯作者：
WILLIAMS, JA
中科院分区：
文献类型：
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作者：
LIDDLE, RA;GOLDFINE, ID;WILLIAMS, JA
开发了一种用于测量人血浆中胆囊收缩素 (CCK) 的灵敏且特异的生物测定法，以确定循环中 CCK 的分子形式、CCK 对进食的反应以及 CCK 在胆囊收缩中的生理作用。首先，定量提取血浆并用十八烷基硅基二氧化硅浓缩，然后测定提取物刺激分离的大鼠胰腺腺泡释放淀粉酶的能力。腺泡对 CCK 高度敏感，而胃泌素在该系统中反应较弱。通过该测定，可检测到胆囊收缩素八肽 (CCK-8) 生物活性的血浆水平低至 0.2 pM。血浆中的 CCK 生物活性被 CCK 拮抗剂联丁酰 cGMP 抑制，并通过针对 CCK 羧基末端的抗体的免疫吸附来消除。所有测试个体均可检测到 CCK 空腹水平，平均值为 1.0 .+-。 0.2 pM（平均值.+-.SE，n = 22）CCK-8 等效物。胃泌素分泌肿瘤患者的血浆 CCK 生物活性正常。喂食混合流质餐后，CCK 水平在 15 分钟内上升至 6.0 .+-。下午 1.6 点。各种食物成分、脂肪、蛋白质和氨基酸都是 CCK 分泌的有效刺激剂；相比之下，葡萄糖导致血浆 CCK 水平显着但较小的升高。凝胶过滤研究确定了人血浆中 CCK 生物活性的 3 种主要形式；用 CCK-33 洗脱的丰富形式，用 CCK-8 洗脱的较小形式，以及 CCK-33 和 CCK-8 之间洗脱的中间形式。胆囊体积的超声波测量表明，在喂食混合流质餐后 30 分钟，该器官的大小减少了 51%。这种收缩与血浆 CCK 水平的增加同时发生。接下来注入 CCK-8 以获得与餐后水平相似的 CCK 水平。这种输注导致胆囊体积减少，类似于进餐时看到的情况。因此，目前的研究表明，CCK 可以在禁食和餐后人血浆中进行生物测定。这些研究还表明CCK可能是胆囊收缩的重要调节因子。
A sensitive and specific bioassay for the measurement of cholecystokinin (CCK) in human plasma was developed to determine the molecular forms of CCK in circulation, CCK responses to feeding, and the physiologic role of CCK in gallbladder contraction. First, plasma was quantitatively extracted and concentrated with octadecylsilylsilica, and the extracts were then assayed for their ability to stimulate amylase release from isolated rat pancreatic acini. Acini were highly sensitive to CCK whereas gastrin reacted only weakly in this system. With the assay, plasma levels of cholecystokinin octapeptide (CCK-8) bioactivity as low as 0.2, pM were detectable. CCK bioactivity in plasma was inhibited by the CCK antagonist, bibutyryl cGMP, and was eliminated by immunoadsorption with an antibody directed against the carboxyl terminus of CCK. Detection of fasting levels of CCK was possible in all individuals tested and averaged 1.0 .+-. 0.2 pM (mean .+-. SE, n = 22) CCK-8 equivalents. Plasma CCK biological activity was normal in patients with gastrin-secreting tumors. After being fed a mixed liquid meal, CCK levels rose within 15 min to 6.0 .+-. 1.6 pM. The individual food components, fat, protein, and amino acids were all potent stimulants of CCK secretion; in contrast, glucose caused a significant but smaller elevation in plasma CCK levels. Gel filtration studies identified 3 major forms of CCK bioactivity in human plasma; an abundant form that eluted with CCK-33, smaller form that eluted with CCK-8, and an intermediate form that eluted between CCK-33 and CCK-8. Ultrasonic measurements of gallbladder volume indicated that this organ decreased 51% in size 30 min after feeding a mixed liquid meal. This contraction occurred coincidentally with the increase in plasma CCK levels. Next CCK-8 was infused to obtain CCK levels similar to postprandial levels. This infusion caused a decrease in gallbladder volume, similar to that seen with a meal. The present studies indicate, therefore, that CCK can be bioassayed in fasting and postprandial human plasma. These studies also suggest that CCK may be an important regulator of gallbladder contraction.