title: Platelet uptake of the pheochromocytoma-scanning agent 131I-meta-iodobenzylguanadine.
abstract: The pheochromocytoma-scanning agent 131I-meta-iodobenzylguanadine (131I-MIBG) was concentrated in the platelets of ten subjects undergoing scans for suspected pheochromocytomas. In vitro studies also demonstrated that 131I-MIBG was concentrated in platelets. In contrast to serotonin, which had maximum in vitro platelet uptake of one hour, the peak in vitro platelet uptake of 131I-MIBG did not occur until six hours. In vitro platelet 131I-MIBG uptake was decreased by 79% to 98% following the neuronal-uptake-blocking agent imipramine. These studies suggest that pheochromocytomas take up 131I-MIBG by a neuronal-pump mechanism. Further studies to determine if 131I-MIBG is taken up by other tumors with a neuronal-pump mechanism, such as carcinoid tumors, will be valuable.
mesh_terms: D019797:3-Iodobenzylguanidine; D000328:Adult; D001792:Blood Platelets / Q000000981:diagnostic imaging / Q000378:metabolism*; D005260:Female; D006801:Humans; D007099:Imipramine / Q000494:pharmacology; D066298:In Vitro Techniques; D007462:Iodobenzenes / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D010673:Pheochromocytoma / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000601:surgery; D011877:Radionuclide Imaging; D012701:Serotonin / Q000378:metabolism; D013997:Time Factors
chemical_list: D007462:Iodobenzenes; D012701:Serotonin; D019797:3-Iodobenzylguanidine; D007099:Imipramine