Expression of dopamine receptors and transporter in neuroendocrine gastrointestinal tumor cells

摘要: C-11- or F-18-DOPA positron emission tomography (DOPA PET) is a new sensitive imaging technique for small neuroendocrine gastrointestinal tumors which evaluates the decarboxylase activity. To further characterize dopaminergic system in tumor cells, we investigated expression of both dopamine receptors and transmembrane transporter (DAT) human pancreatic cell line BON gut STC-1. Both STC-1 cells expressed mRNA D2-D5 DAT. receptor D1 was detected only. D2 D5 DAT also demonstrated immunocytochemically. For functional characterization intracellular cAMP levels ([cAMP]i) were determined. Whereas D1-like (D1/D5) agonist SKF 38393 increased [cAMP]i, [cAMP]i decreased by D2-like (D2-D4) quinpirole cells. Functional activity was, however, not either line. The presence suggests an autocrine and/or paracrine function Yet neither nor are likely to contribute positive DOPA PET tumors. However, these molecules may be diagnostic importance when applying other tracers.