title: Imaging the primate adrenal medulla with [123I] and [131I] meta-iodobenzylguanidine: concise communication.
abstract: An evaluation of radioiodinated meta-iodobenzylguanidine (m-IBG) as an adrenomedullary imaging agent is reported in 15 rhesus monkeys. Scintiscans of the monkey adrenal medulla have been obtained with [123I]- and [m-131I]IBG at 2-6 days after injection. The imaging superiority of m-IBG over its positional isomer, para-iodobenzylguanidine (p-IBG), is documented in both dogs and monkeys. Administration of reserpine, a depletor of catecholamine stores, markedly lowers the [m-131I]-IBG content of the dog adrenal medulla, but the adrenergic blocking agents phenoxybenzamine and propranolol have no effect. Subcellular fractionation of the dog's adrenal medullae reveals that m-IBG is sequestered mainly in the chromaffin storage granules. The results of this study suggest that radioiodinated m-IBG, previously reported to image the primate myocardium, also merits evaluation as a clinical radiopharmaceutical for the adrenal medulla.
mesh_terms: D019797:3-Iodobenzylguanidine; D000313:Adrenal Medulla / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000648:ultrastructure; D000818:Animals; D002837:Chromaffin Granules / Q000378:metabolism; D004285:Dogs; D005260:Female; D006146:Guanidines / Q000378:metabolism; D007457:Iodine Radioisotopes; D007462:Iodobenzenes; D008253:Macaca mulatta; D008297:Male; D011877:Radionuclide Imaging; D012110:Reserpine / Q000494:pharmacology; D014018:Tissue Distribution
chemical_list: D006146:Guanidines; D007457:Iodine Radioisotopes; D007462:Iodobenzenes; C025423:4-iodobenzylguanidine; D019797:3-Iodobenzylguanidine; D012110:Reserpine