title: In vivo measurement of dopamine receptors in pituitary adenomas using positron emission tomography.
abstract: Patients with pituitary adenomas were examined with positron emission tomography (PET) with the administration of the 11C-labelled dopamine-D2 antagonists N-methylspiperone and raclopride. The studies were repeated after protection of the D2-receptors with Haloperidol to enable a separation of specific and unspecific receptor binding. The receptor binding was evaluated by visual inspection and with the application of a kinetic model. The results showed marked specific dopamine-D2 receptor binding in the prolactinomas and minimal or no such binding in the hormonally inactive adenomas. The two tracers 11C-raclopride and 11C-N-methylspiperone showed qualitatively the same result although raclopride resulted in a higher tumor to normal brain ratio. In conclusion, PET is a valuable complement to other radiologic techniques like computed tomography and magnetic resonance imaging in the evaluation of pituitary adenomas. An assessment of the dopamine-D2 receptors in the adenomas has a direct influence on the choice of treatment because adenomas with high amounts of receptors are in most cases effectively treated with dopamine agonists like bromocriptine.
authors.affiliation: Department of Neurology, University Hospital, Uppsala, Sweden.
authors.forename: C
authors.initials: C
authors.lastname: Muhr
authors.forename: M
authors.initials: M
authors.lastname: Bergström
authors.forename: P O
authors.initials: PO
authors.lastname: Lundberg
authors.forename: K
authors.initials: K
authors.lastname: Bergström
authors.forename: B
authors.initials: B
authors.lastname: Långström
mesh_terms: D000236:Adenoma / Q000737:chemistry / Q000000981:diagnostic imaging*; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010911:Pituitary Neoplasms / Q000737:chemistry / Q000000981:diagnostic imaging*; D011954:Receptors, Dopamine / Q000032:analysis*; D014055:Tomography, Emission-Computed
chemical_list: D011954:Receptors, Dopamine