Molecular forms of cholecystokinin in plasma from normal and gastrectomized human subjects following a fat meal.
The present study was undertaken to characterize molecular forms of cholecystokinin (CCK) in human fat-stimulated plasma by Sephadex G50 column chromatography followed by radioimmunoassays employing 3 different region-specific antibodies. CCK was extracted and concentrated from plasma of healthy subjects by adsorption to SEP-PAK C18 cartridges and from plasma of gastrectomized patients by addition of 96% ethanol. Antibody 1703 binds to carboxy-terminal CCK-peptides containing at least 14 amino acid residues, antibody T204 to sulfated carboxy-terminal CCK-peptides and antibody 5135 to carboxy-terminal forms of CCK and gastrin. Four molecular forms of CCK were consistently demonstrated; peak I eluted in the void volume and comprised 1.8-10.2% of CCK-immunoreactivity, peak II eluted between the void volume and the CCK-33/39 standard and comprised 9.8-21.6%, peak III eluted at the position of the CCK-33/39 standard and comprised 42.4-55.4%, and peak IV eluted between the CCK-33/39 and CCK-14 standards and comprised 25.4-40.1% of CCK immunoreactivity. Since these 4 molecular forms reacted to all 3 CCK-antibodies it is likely that they contain the sulfated tyrosyl and carboxy-terminal regions of CCK and, therefore, possess biological activity.
Department of Gastroenterology and Hepatology, University Hospital Leiden, The Netherlands.
J B
JB
Jansen
C B
CB
Lamers
D000328:Adult; D000906:Antibodies; D000936:Antigen-Antibody Complex; D002766:Cholecystokinin / Q000097:blood* / Q000302:isolation & purification; D002850:Chromatography, Gel; D004041:Dietary Fats; D004435:Eating; D005743:Gastrectomy; D006801:Humans; D008297:Male; D008875:Middle Aged; D012016:Reference Values
D000906:Antibodies; D000936:Antigen-Antibody Complex; D004041:Dietary Fats; D002766:Cholecystokinin