Molecular Forms of Cholecystokinin in Human Bile in Patients with Obstructive Jaunice

Abstract

Cholecystokinins (CCKs) in extracts of human bile of patients with obstructive jaundice were compared with those in bile of patients without obstructive jaundice. Cholecystokinins were purified from human bile using chloroform with a Sephadex G-25 column and a Sep-Pak C₁₈cartridge and isolated by high performance liquid chromatography (HPLC) . The different molecular forms of cholecystokinin ( CCK ), especially cholecystokinin tetrapep-tide ( CCK-4), cholecystokinin octapeptide (CCK-8) and cholecystokinin triacontatriapeptide (CCK-33) in human bile were isolated by HPLC and measured by radioimmunoassay and bioassay. The concentrations of CCK measured by radioimmunoassay (RIA) were consistent with those by bioassay, indicating that bioactivity of CCK is not attenuated in human bile. Moreover, the CCK receptor antagonist L-364, 718 (10 nM) completely inhibited the bioactivity of CCK in human bile. We found that the predominant molecular forms of the CCK in human bile of patients with obstructive jaundice are larger than those in bile of patients without obstructive jaundice. These results suggested that the liver may be the major site of CCK extraction or degradation and may therefore play a significant role in CCK turnover.