Functional and biochemical characterization of the human gallbladder muscularis cholecystokinin receptor

Birgit Schjoldager, Xavier Molero, Laurence J. Miller

Research output: Contribution to journalArticle

40 Scopus citations

Abstract

Gallbladders removed at cholecystectomy are a potentially useful source of human receptor for the gastrointestinal peptide hormone cholecystokinin (CCK). Seven healthy gallbladders (removed incidentally at time of resection of hepatic metastases) and 50 diseased gallbladders were studied. Cholecystokinin radioligand binding to an enriched plasma membrane preparation from these tissues was shown to be rapid, reversible, temperature-dependent, saturable, specific, and high-affinity. Computer analysis of equilibrium binding data using the Ligand program best fit a single class of binding sites with Kd = 1.0 ± 0.1 nM (mean ± SEM). This was similar in health and disease, with no apparent differences related to age, gender, or body habitus. The structural specificity for binding to this site correlated well with relative potencies for CCK-gastrin peptides to stimulate gallbladder contraction. To biochemically characterize this receptor, we used a battery of reagents, including "long" (125I-Bolton Hunter-CCK-33) and "short" 125I-d-Tyr-Gly-[(Nle28,31)CCK-26-33] probes that were crosslink able through their amino terminus and a monofunctional probe with a photolabile group at its carboxyl terminus 125I-d-Tyr-Gly[(Nle28,31,pNO2-Phe33)CCK-26-33]. All probes specifically labeled a human gallbladder muscularis protein of Mr = 85,000-95,000, which was also independent of diagnosis. Labeling of this band was inhibited in a concentration-dependent manner by CCK-8 and by L-364,718. Thus, the CCK receptor present on the very common surgically removed human gallbladder is functionally and biochemically intact and is useful for further characterization.

Original languageEnglish (US)
Pages (from-to)1119-1125
Number of pages7
JournalGastroenterology
Volume96
Issue number4
DOIs
StatePublished - Apr 1989

    Fingerprint

ASJC Scopus subject areas

  • Hepatology
  • Gastroenterology

Cite this