OBJECTIVE: We introduce a novel liquid chromatographic tandem-mass spectrometric method for simultaneous measurements of urinary catecholamines and their free O-methylated metabolites, which we compare to the deconjugated metabolites. METHODS: Method performance was validated for recovery, linearity, precision and accuracy, analyte stability, ion suppression and carry over. Results from 53 patients with and 138 volunteers without pheochromocytoma were compared. RESULTS: Analyte recoveries ranged from 60 to 96% and intra- and inter-assay coefficients of variation from 2.7 to 13.2%. The method showed excellent linearity over 3 orders of magnitude with analytical sensitivity sufficient to measure to 1.2 nmol/L. Free O-methylated metabolites were excreted at less than 20% the rates of the deconjugated metabolites, but were easily measureable. Increases in urinary normetanephrine in pheochromocytoma patients relative to volunteers were higher for free than deconjugated metabolites and higher for both than for norepinephrine (10 vs 5.5 vs 3.7 fold increases). In contrast, relative increases in urinary free versus deconjugated metanephrine (2.7 and 3.2) and methoxytyramine (2.1 and 1.9) did not differ, but for methoxytyramine were larger than for dopamine (1.2). CONCLUSION: Measurements of urinary catecholamines and their free O-methylated metabolites by our method provide potential advantages over urinary deconjugated metanephrines for diagnosis of pheochromocytoma.
OBJECTIVE: We introduce a novel liquid chromatographic tandem-mass spectrometric method for simultaneous measurements of urinary catecholamines and their free O-methylated metabolites, which we compare to the deconjugated metabolites. METHODS: Method performance was validated for recovery, linearity, precision and accuracy, analyte stability, ion suppression and carry over. Results from 53 patients with and 138 volunteers without pheochromocytoma were compared. RESULTS: Analyte recoveries ranged from 60 to 96% and intra- and inter-assay coefficients of variation from 2.7 to 13.2%. The method showed excellent linearity over 3 orders of magnitude with analytical sensitivity sufficient to measure to 1.2 nmol/L. Free O-methylated metabolites were excreted at less than 20% the rates of the deconjugated metabolites, but were easily measureable. Increases in urinary normetanephrine in pheochromocytomapatients relative to volunteers were higher for free than deconjugated metabolites and higher for both than for norepinephrine (10 vs 5.5 vs 3.7 fold increases). In contrast, relative increases in urinary free versus deconjugated metanephrine (2.7 and 3.2) and methoxytyramine (2.1 and 1.9) did not differ, but for methoxytyramine were larger than for dopamine (1.2). CONCLUSION: Measurements of urinary catecholamines and their free O-methylated metabolites by our method provide potential advantages over urinary deconjugated metanephrines for diagnosis of pheochromocytoma.
Authors: Martin Ullrich; Ralf Bergmann; Mirko Peitzsch; Marc Cartellieri; Nan Qin; Monika Ehrhart-Bornstein; Norman L Block; Andrew V Schally; Jens Pietzsch; Graeme Eisenhofer; Stefan R Bornstein; Christian G Ziegler Journal: Endocrinology Date: 2014-08-19 Impact factor: 4.736
Authors: Susan Richter; Mirko Peitzsch; Elena Rapizzi; Jacques W Lenders; Nan Qin; Aguirre A de Cubas; Francesca Schiavi; Jyotsna U Rao; Felix Beuschlein; Marcus Quinkler; Henri J Timmers; Giuseppe Opocher; Massimo Mannelli; Karel Pacak; Mercedes Robledo; Graeme Eisenhofer Journal: J Clin Endocrinol Metab Date: 2014-07-11 Impact factor: 5.958
Authors: Yaxin An; Manja Reimann; Jimmy Masjkur; Katharina Langton; Mirko Peitzsch; Timo Deutschbein; Martin Fassnacht; Natalie Rogowski-Lehmann; Felix Beuschlein; Stephanie Fliedner; Anthony Stell; Aleksander Prejbisz; Andrzej Januszewicz; Jacques Lenders; Stefan R Bornstein; Graeme Eisenhofer Journal: Int J Obes (Lond) Date: 2018-03-03 Impact factor: 5.095
Authors: Martin Ullrich; Ralf Bergmann; Mirko Peitzsch; Erik F Zenker; Marc Cartellieri; Michael Bachmann; Monika Ehrhart-Bornstein; Norman L Block; Andrew V Schally; Graeme Eisenhofer; Stefan R Bornstein; Jens Pietzsch; Christian G Ziegler Journal: Theranostics Date: 2016-03-10 Impact factor: 11.556