{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,18]],"date-time":"2026-10-18T18:11:52Z","timestamp":1792347112763,"version":"4.4.0"},"reference-count":19,"publisher":"SAGE Publications","issue":"4","license":[{"start":{"date-parts":[[2019,4,11]],"date-time":"2019-04-11T00:00:00Z","timestamp":1554940800000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/journals.sagepub.com\/page\/policies\/text-and-data-mining-license"}],"content-domain":{"domain":["journals.sagepub.com"],"crossmark-restriction":true},"short-container-title":["Ann Clin Biochem"],"published-print":{"date-parts":[[2019,7]]},"abstract":"<jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Levodopa (L-DOPA) provided to patients with Parkinson\u2019s disease causes an increase in dopamine and methoxytyramine blood concentration which may lead to erroneous diagnosis of dopamine-producing tumours based on a plasma fractionated metanephrines and methoxytyramine assay. Considering that oral L-DOPA is mainly transformed in the gut wall into dopamine and methoxytyramine, we hypothesize that patients treated with L-DOPA produce predominantly sulphated methoxytyramine, whereas dopamine-producing tumours, devoid of sulfotransferase, will secrete free methoxytyramine. These metabolic differences may allow for discrimination between the two groups of patients through methoxytyramine plasma concentration.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>We retrospectively investigated a cohort of 16 patients with a dopamine-secreting pheochromocytoma or paraganglioma and 22 patients treated for Parkinson\u2019s disease to see whether the metabolic ratio of free and sulphated methoxytyramine differs.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Receiver operating characteristic curve analysis indicates an absolute separation between the two groups when using a cut-off of free\/total methoxytyramine (sum of free and sulphated methoxytyramine) ratio of 0.0059, corresponding to a free methoxytyramine fraction of 0.59% ( P\u2009&lt;\u20090.0001, AUC 1.0 indicating 100% sensitivity and specificity).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>Dopamine secreted by tumours and exogenous dopamine (from Parkinson\u2019s disease treatment) follow different metabolic pathways. We observed that free\/total methoxytyramine ratio may be a useful tool in distinguishing between patients with a dopamine-secreting tumour from patients treated with L-DOPA when clinical information is incomplete or lacking.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1177\/0004563219835263","type":"journal-article","created":{"date-parts":[[2019,4,12]],"date-time":"2019-04-12T01:09:20Z","timestamp":1555031360000},"page":"466-471","update-policy":"https:\/\/doi.org\/10.1177\/sage-journals-update-policy","source":"Crossref","is-referenced-by-count":2,"title":["High concentration of plasma methoxytyramine: dopamine-producing tumour or Parkinson\u2019s disease therapy?"],"prefix":"10.1177","volume":"56","author":[{"given":"Haithem","family":"Chtioui","sequence":"first","affiliation":[{"name":"Service of Clinical Pharmacology, University Hospital of Lausanne (CHUV), Lausanne, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Samira M","family":"Sadowski","sequence":"additional","affiliation":[{"name":"Service of Thoracic and Endocrine Surgery, University Hospital of Geneva, Geneva, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bettina","family":"Winzeler","sequence":"additional","affiliation":[{"name":"Department of Endocrinology, University Hospital of Basel, Basel, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Oliver","family":"Tschopp","sequence":"additional","affiliation":[{"name":"Department of Endocrinology, University Hospital of Zurich, Zurich, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Eric","family":"Grouzmann","sequence":"additional","affiliation":[{"name":"Service of Clinical Pharmacology, University Hospital of Lausanne (CHUV), Lausanne, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Karim","family":"Abid","sequence":"additional","affiliation":[{"name":"Service of Clinical Pharmacology, University Hospital of Lausanne (CHUV), Lausanne, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"179","published-online":{"date-parts":[[2019,4,11]]},"reference":[{"key":"bibr1-0004563219835263","doi-asserted-by":"publisher","DOI":"10.1038\/nrneurol.2009.55"},{"key":"bibr2-0004563219835263","doi-asserted-by":"publisher","DOI":"10.1016\/j.ejim.2007.06.006"},{"key":"bibr3-0004563219835263","doi-asserted-by":"publisher","DOI":"10.1177\/106002809603000523"},{"key":"bibr4-0004563219835263","doi-asserted-by":"publisher","DOI":"10.1136\/jnnp.51.5.728-a"},{"key":"bibr5-0004563219835263","doi-asserted-by":"publisher","DOI":"10.1177\/0004563213487894"},{"key":"bibr6-0004563219835263","doi-asserted-by":"publisher","DOI":"10.1210\/jc.2004-2025"},{"key":"bibr7-0004563219835263","first-page":"5153","volume":"30","author":"Van Der Horst-Schrivers AN","year":"2010","journal-title":"Anticancer 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