Gastric inhibitory polypeptide (GIP) binding sites in rat brain.


Journal Article

Synthetic porcine gastric inhibitory polypeptide (GIP) was iodinated and purified by reverse-phase HPLC and used to localize saturable [125I]GIP binding sites by radioligand binding to frozen sections of rat brain followed by autoradiography. Saturable [125I]GIP binding sites were expressed in several brain regions including cerebral cortex, anterior olfactory nucleus, lateral septal nucleus, subiculum, inferior colliculus, and inferior olive. Saturable [125I]GIP binding was time dependent, reversible, high affinity, and specific for GIP. Scatchard analysis of equilibrium binding resulted in an estimated dissociation constant (Kd) of 16-62 pM for the rat brain [125I]GIP binding sites. Peptides with amino acid sequences similar to GIP such as secretin, vasoactive intestinal polypeptide (VIP), glucagon, and peptide histidine isoleucine (PHI) only partially inhibited saturable [125I]GIP binding at concentrations approximately 10,000-100,000-fold higher than GIP. Saturable [125I]GIP binding was not observed in other rat organs surveyed such as spinal cord, pituitary, stomach, small intestine, colon, pancreas, liver, heart, or skeletal muscle. We conclude that a saturable [125I]GIP binding site with the pharmacological properties of an authentic GIP receptor is expressed in certain regions of the rat brain.

Full Text

Cited Authors

  • Kaplan, AM; Vigna, SR

Published Date

  • 1994

Published In

Volume / Issue

  • 15 / 2

Start / End Page

  • 297 - 302

PubMed ID

  • 8008635

Pubmed Central ID

  • 8008635

International Standard Serial Number (ISSN)

  • 0196-9781

Digital Object Identifier (DOI)

  • 10.1016/0196-9781(94)90016-7


  • eng

Conference Location

  • United States