title: Synthesis and evaluation of radioiodinated substituted beta-naphthylalanine as a potential probe for pancreatic beta-cells imaging.
abstract: A non-invasive imaging technique capable of relating a signal from the beta-cells to their mass will be of immense value in understanding the progression of diabetes. Several molecular markers have indeed been identified and investigations are ongoing aimed at accomplishing the said goal. These include pancreatic islet antigen (IC-2), somatostatin receptors (SSTRs), and sulfonylurea receptors (SURs) on the pancreatic beta-cells. Therefore investigations exploiting the potential application of the radiolabeled ligands for these receptors for beta-cell imaging are receiving intensive research attention. Radioiodinated peptidomimetic based on beta-naphthylalanine and n-hexanediamine has been synthesized. The molecule was subjected to in vitro and in vivo evaluation. Radioligand binding studies on CHO cell line expressing the SSTR2 showed very low affinity. Nonetheless, biodistribution in normal mice showed significant uptake in the pancreas. There was partial blockage of the pancreatic uptake when excess of the peptidomimetic was coinjected. The result implies that the pancreatic uptake was receptor mediated but may not involve the SSTR2 and therefore warrants further investigation.
authors.affiliation: Cyclotron and Radiopharmaceuticals Department, King Faisal Specialist Hospital and Research Centre, P.O. Box 3354, Riyadh 11211, Kingdom of Saudi Arabia. Amarty@kfshrc.edu.sa
authors.forename: J K
authors.initials: JK
authors.lastname: Amartey
authors.forename: C
authors.initials: C
authors.lastname: Esguerra
authors.forename: I
authors.initials: I
authors.lastname: Al-Jammaz
authors.forename: R S
authors.initials: RS
authors.lastname: Parhar
authors.forename: B
authors.initials: B
authors.lastname: Al-Otaibi
mesh_terms: D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D050417:Insulin-Secreting Cells / Q000000981:diagnostic imaging* / Q000378:metabolism; D007457:Iodine Radioisotopes / Q000737:chemistry*; D007553:Isotope Labeling / Q000379:methods; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D051379:Mice; D008808:Mice, Inbred CBA; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000138:chemical synthesis*; D014018:Tissue Distribution; D015091:beta-Alanine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism
chemical_list: D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D015091:beta-Alanine; C063914:beta-naphthylalanine