[<sup>177</sup>Lu]Lu-DOTA-Ahx-Lys40-Exendin-4 ([<sup>177</sup>Lu]Lu-DOTA-Exendin-4) is a potential agent for radiotherapy of insulinomas owing to its specificity towards GLP-1 (Glucagon like peptide-1) receptors over-expressed on such cancers.
The aim of this study was to assess the diagnostic accuracy of a Tc-99m-labelled GLP-1R agonist [Lys<sup>40</sup>(AhxHYNIC-[<sup>99m</sup>Tc]EDDA)NH<sub>2</sub>]-exendin-4 for localization of occult insulinoma.
[<sup>68</sup>Ga]Ga-NOTA-MAL-Cys<sup>39</sup>-exendin-4 was easily synthesized with high yield, favorable biodistribution and high affinity to islet tumor cell, making the tracer may have great potential in the detection of GLP-1R positive tumor such as an insulinoma.
The present study showed that <sup>18</sup>F-FDOPA PET/CT combined with carbidopa premedication and early pancreatic acquisitions is a valuable diagnostic option in patients with insulinoma when GLP1R-based imaging is not available.
The BV-mediated exogenous hGLP-1R in target cells showed same ligand-receptor binding characteristics compared with its counterpart in insulinoma cells.
As highly expressed in insulinomas, the glucagon-like peptide-1 receptor (GLP-1R) is believed to be an attractive target for diagnosis, localization, and treatment with radiolabeled exendin 4.
Glucagon-like peptide 1 receptor analogs have recently shown promising results in preoperative localization of these tumors, as all insulinomas express glucagon-like peptide 1 receptors.
Being highly expressed in insulinomas, the glucagonlike peptide-1 receptor (GLP-1R) is a potential target for diagnosis, localization, and treatment with the radiolabeled GLP-1R agonist exendin.
The purpose of the study was to test the diagnostic accuracy and clinical impact of glucagon-like peptide-1 receptor (GLP-1R) PET/CT using <sup>68</sup>Ga-DOTA-exendin-4 in consecutive adult patients referred for localisation of insulinomas.
In this study, we synthesized a novel indium-111 (<sup>111</sup>In)-benzyl-diethylenetriaminepentaacetic acid (<sup>111</sup>In-BnDTPA)-conjugated exendin(9-39), <sup>111</sup>In-BnDTPA-exendin(9-39), and evaluated its utility as a probe for the SPECT imaging of insulinoma. natIn-BnDTPA-exendin(9-39) exhibited a high affinity for GLP-1R (IC<sub>50</sub>=2.5nM), stability in plasma, and a specific activity that improved following reactions with a solvent and solubilizer.
Benign insulinomas express the glucagon-like peptide-1 receptor (GLP-1R, which recognizes exendin-4 and low levels of the somatostatin receptor (SSTR, which recognizes octreotide), whereas malignant insulinomas overexpress SSTR and low levels of GLP-1R.
Targeting GLP-1R by (111)In-DOTA-exendin-4 or (111)In-DPTA-exendin-4 offers a new approach that permits the successful localization of small benign insulinomas.