[3H] Boc [Nle28, 31]CCK27-33, a new highly labelled ligand for CCK receptors: binding on brain and on pancreas

Life Sci. 1985 Dec 30;37(26):2483-90. doi: 10.1016/0024-3205(85)90605-8.

Abstract

Preliminary results on the binding of [3H]Boc[Nle28, 31]CCK27-33, designated [3H]Boc[diNle]CCK7, on mouse brain and rat pancreas membranes are presented. This new ligand for CCK receptors possesses a high specific activity (144 Ci/mmole), and binds in a saturable manner to mouse brain (Kd = 0.49 nM, Bmax = 49 fmoles/mg protein) and rat pancreas (Kd = 4.4 nM, Bmax = 696 fmoles/mg protein). Unlabelled Boc[diNle]CCK7 displaces [125I]CCK8 from its binding sites on mouse brain membranes with a high affinity, slightly superior to that of CCK8. The order of potencies to displace [3H]Boc[diNle]CCK7 from its binding sites was the same in mouse brain and rat pancreas: [3H]Boc[diNle]CCK7 greater than CCK8, Boc-CCK7 greater than non-sulfated CCK8, the pancreas binding sites being more discriminative than the brain binding sites. Thus, [3H]Boc[diNle]CCK7 is a very promising new probe for the characterization of CCK receptors and their interaction with different CCK fragments.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Binding, Competitive
  • Brain / metabolism*
  • Cholecystokinin / metabolism*
  • Kinetics
  • Magnesium / pharmacology
  • Male
  • Mice
  • Pancreas / metabolism*
  • Peptide Fragments*
  • Receptors, Cell Surface / metabolism*
  • Receptors, Cholecystokinin
  • Sincalide / metabolism
  • Structure-Activity Relationship

Substances

  • Peptide Fragments
  • Receptors, Cell Surface
  • Receptors, Cholecystokinin
  • Cholecystokinin
  • cholecystokinin (27-33), tert-butyloxycarbonyl-Nle(28,31)-
  • Magnesium
  • Sincalide