{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,28]],"date-time":"2026-09-28T23:17:39Z","timestamp":1790637459230,"version":"4.1.0"},"reference-count":48,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2018,5,11]],"date-time":"2018-05-11T00:00:00Z","timestamp":1525996800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Nutrients"],"abstract":"<jats:p>Central nervous serotonin (5-HT) can influence behaviour and neuropsychiatric disorders. Evidence from animal models suggest that lowered levels of neuropeptide Y (NPY) may have similar effects, although it is currently unknown whether decreased central nervous 5-HT impact NPY concentrations. Given that the production of NPY is dependent on the essential amino acid methionine (MET), it is imperative to account for the presence of MET in such investigations. Hence, this study sought to examine the effects of acute tryptophan depletion (ATD; a dietary procedure that temporarily lowers central nervous 5-HT synthesis) on serum concentrations of NPY, whilst using the potential renal acid load indicator (PRAL) to control for levels of MET. In a double-blind repeated measures design, 24 adult humans randomly received an AA-load lacking in TRP (ATD) on one occasion, and a balanced control mixture with TRP (BAL) on a second occasion, both with a PRAL of nearly 47.3 mEq of MET. Blood samples were obtained at 90, 180, and 240 min after each of the AA challenges. ATD, and therefore, diminished substrate availability for brain 5-HT synthesis did not lead to significant changes in serum NPY concentrations over time, compared to BAL, under an acute acidotic stimulus.<\/jats:p>","DOI":"10.3390\/nu10050594","type":"journal-article","created":{"date-parts":[[2018,5,14]],"date-time":"2018-05-14T02:57:20Z","timestamp":1526266640000},"page":"594","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Effects of Dietary Acute Tryptophan Depletion (ATD) on NPY Serum Levels in Healthy Adult Humans Whilst Controlling for Methionine Supply\u2014A Pilot Study"],"prefix":"10.3390","volume":"10","author":[{"given":"Janice W. Y.","family":"Wong","sequence":"first","affiliation":[{"name":"Centre &amp; Discipline of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, School of Medicine, Division of Psychiatry and Clinical Neurosciences and Division of Paediatrics and Child Health, The University of Western Australia, 6009 Perth, Australia"},{"name":"Specialised Child and Adolescent Mental Health Services (CAMHS), Department of Health, 6009 Perth, Australia"},{"name":"Telethon Kids Institute, 6009 Perth, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hugo A. E.","family":"Morandini","sequence":"additional","affiliation":[{"name":"Centre &amp; Discipline of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, School of Medicine, Division of Psychiatry and Clinical Neurosciences and Division of Paediatrics and Child Health, The University of Western Australia, 6009 Perth, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Vita L. S.","family":"Dingerkus","sequence":"additional","affiliation":[{"name":"Acute Child and Adolescent Mental Health Services (CAMHS), Department of Health, 6009 Perth, Australia"},{"name":"Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University Hospital, 52074 Aachen, Germany"},{"name":"Department of Ophthalmology, Triemli Hospital Z\u00fcrich, CH-8063 Z\u00fcrich, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tilman J.","family":"Gaber","sequence":"additional","affiliation":[{"name":"Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University Hospital, 52074 Aachen, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kevin C.","family":"Runions","sequence":"additional","affiliation":[{"name":"Centre &amp; Discipline of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, School of Medicine, Division of Psychiatry and Clinical Neurosciences and Division of Paediatrics and Child Health, The University of Western Australia, 6009 Perth, Australia"},{"name":"Telethon Kids Institute, 6009 Perth, Australia"},{"name":"Community Child and Adolescent Mental Health Services (CAMHS), Department of Health, 6009 Perth, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5637-7769","authenticated-orcid":false,"given":"Pradeep","family":"Rao","sequence":"additional","affiliation":[{"name":"Centre &amp; Discipline of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, School of Medicine, Division of Psychiatry and Clinical Neurosciences and Division of Paediatrics and Child Health, The University of Western Australia, 6009 Perth, Australia"},{"name":"Department of Ophthalmology, Triemli Hospital Z\u00fcrich, CH-8063 Z\u00fcrich, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Simone","family":"Mahfouda","sequence":"additional","affiliation":[{"name":"Centre &amp; Discipline of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, School of Medicine, Division of Psychiatry and Clinical Neurosciences and Division of Paediatrics and Child Health, The University of Western Australia, 6009 Perth, Australia"},{"name":"Telethon Kids Institute, 6009 Perth, Australia"},{"name":"School of Psychological Sciences, Faculty of Science, The University of Western Australia, 6009 Perth, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Katrin","family":"Helmbold","sequence":"additional","affiliation":[{"name":"Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University Hospital, 52074 Aachen, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sarah","family":"Bubenzer-Busch","sequence":"additional","affiliation":[{"name":"Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University Hospital, 52074 Aachen, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rebecca","family":"Koenemann","sequence":"additional","affiliation":[{"name":"Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University Hospital, 52074 Aachen, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Richard M.","family":"Stewart","sequence":"additional","affiliation":[{"name":"Centre &amp; Discipline of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, School of Medicine, Division of Psychiatry and Clinical Neurosciences and Division of Paediatrics and Child Health, The University of Western Australia, 6009 Perth, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Florian D.","family":"Zepf","sequence":"additional","affiliation":[{"name":"Centre &amp; Discipline of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, School of Medicine, Division of Psychiatry and Clinical Neurosciences and Division of Paediatrics and Child Health, The University of Western Australia, 6009 Perth, Australia"},{"name":"Specialised Child and Adolescent Mental Health Services (CAMHS), Department of Health, 6009 Perth, Australia"},{"name":"Telethon Kids Institute, 6009 Perth, Australia"},{"name":"Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University Hospital, 52074 Aachen, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2018,5,11]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"743","DOI":"10.1016\/S2215-0366(15)00232-1","article-title":"The serotonin transporter in psychiatric disorders: Insights from pet imaging","volume":"2","author":"Spies","year":"2015","journal-title":"Lancet Psychiatry"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1103","DOI":"10.1038\/nn1964","article-title":"Long story short: The serotonin transporter in emotion regulation and social cognition","volume":"10","author":"Canli","year":"2007","journal-title":"Nat. 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