Measurement and characterisation of human cholecystokinin-like immunoreactivity (CCK-LI) in tissues by radioimmunoassay

A. J. Bacarese-Hamilton, T. E. Adrian, S. R. Bloom

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9 Citations (Scopus)


Two radioimmunoassays specific for cholecystokinin-like immunoreactivity (CCK-LI) in human tissue are described. The first assay employed an antiserum (Z-69) directed to the sulphated tyrosine at the C-terminal end of CCK-33 and measured all biologically active molecular forms of CCK except the controversial C-terminal tetrapeptide amide (CCK4). The sensitivity of this assay was 0.6 pmol/g. A second assay (employing antiserum Z-91) measured CCK-LI forms larger than the octapeptide and had a sensitivity of 0.2 pmol/g. Both assays were characterised with endogenous human peptides. Acid (pH 2.5) and neutral extracts (pH 6.5) of human intestine and brain were assessed for CCK-LI concentrations and gel chromatography performed in the presence of 6 mol/1 urea to elucidate the various molecular forms. Human cerebral cortex CCK-LI was almost all sulphated CCK-8, but large molecular mass forms were present, particularly in acid extracts, forming about 10% of the whole. Human duodenum and jejunum contained approximately equal amounts of large CCK, CCK 33/39 and of CCK-8. Both intestine and brain possess not yet isolated sulphated molecular forms which eluted between the pure CCK-8 and CCK-33/39 standards. The results obtained from this study indicate that the biosynthesis of CCK in human brain and gut is quantitatively different.

Original languageEnglish
Pages (from-to)213-224
Number of pages12
JournalClinica Chimica Acta
Issue number2-3
Publication statusPublished - Dec 29 1984
Externally publishedYes


  • Biosynthesis
  • Gel filtration chromatography
  • Human cholecystokinin-like immunoreactivity (CCK-LI)
  • Molecular heterogeneity
  • Specific radioimmunoassay

ASJC Scopus subject areas

  • Biochemistry
  • Clinical Biochemistry
  • Biochemistry, medical


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