生物法测定血浆胆囊收缩素活性

Bioassay for Plasma Cholecystokinin Bioactivity

本文根据胆囊收缩素(CCK)在生理浓度下可刺激离体胰腺泡分泌淀粉酶的特性,来测定血浆CCK浓度。此方法不受血浆中胃泌素的干扰,可反映全部有生物活性的CCK分子,灵敏度为0.86pmol/L CCK-8当量。本文对11例正常人空腹及餐后血浆CCK浓度进行了测定。

A sensitive and specific bioassay for the measurement of plasma cholecysto-kinin (CCK) is reported. CCK was extracted from plasma by SEP-PAK cartridges and the extracts were measured for CCK levels based on their ability to stimulate amylase release from dispersed rat pancreatic acini. Plasma CCK levels as low as 0.86 pmol/L (CCK-8 equivalent) were detectable. Gastrin in physiological concentration did not affect the bioassay. The amylase release stimulated by plasma extracts was abolished by Bt2-cGMP, a specific CCK receptor antagonist, indicating that there might be no secretin or VIP in plasma extracts. With this bioassay, fasting and postprandial plasma CCK levels of 11 normal volunteers were determined. The fasting level of CCK was 0.95±0.22 pmol/L (X±SE). It increased to 2.98±0.67 pmol/L 15 minutes after feeding and remained significantly higher than the fasting level during a 60-minute period.