Melatonin and Dopamine as Biomarkers to Optimize Treatment in Phenylketonuria: Effects of Tryptophan and Tyrosine Supplementation - 25/06/14
Abstract |
Objective |
To determine whether additional supplementation of tryptophan (Trp) and tyrosine (Tyr) improve serotonin and dopamine metabolism in individuals with phenylketonuria treated with large neutral amino acid (LNAA) tablets.
Study design |
Ten adult individuals with phenylketonuria participated in a randomized, double-blind, placebo-controlled cross-over study consisting of three 3-week phases: washout, treatment with LNAA tablets plus supplementation with either Trp and Tyr tablets or placebo, and LNAA tablets plus the alternate supplementation. An overnight protocol to measure blood melatonin, a serotonin metabolite in the pinealocytes, and urine 6-sulfatoxymelatonin and dopamine in first-void urine specimens was conducted after each phase.
Results |
Serum melatonin and urine 6-sulfatoxymelatonin and dopamine levels were increased in the LNAA phase (LNAA plus placebo) compared with the washout phase. Serum melatonin and urine 6-sulfatoxymelatonin were not increased in the active phase (LNAA plus Trp + Tyr) compared with the LNAA phase, although plasma Trp:LNAA was increased compared with the LNAA phase. Among 7 subjects with a plasma Trp/LNAA >0.03, a negative correlation between urine 6-sulfatoxymelatonin and plasma phenylalanine levels was observed (r = −0.072). Urine dopamine levels and plasma Tyr:LNAA were increased in the active phase compared with the LNAA phase.
Conclusion |
Melatonin levels were not increased with the higher dose of Trp supplementation, but dopamine levels were increased with the higher dose of Tyr supplementation. Serotonin synthesis appears to be suppressed by high phenylalanine levels at the Trp hydroxylase level.
Le texte complet de cet article est disponible en PDF.Keyword : AUC, CNS, LAT1, LNAA, LNAA + TT, Phe, PKU, TH, TPH, Trp, Tyr
Plan
| Funded by Applied Nutrition and the National Institutes of Health (NIH)/National Center for Research Resources (SC-CTSI UL1 RR031986). Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the NIH. The authors declare no conflicts of interest. |
Vol 165 - N° 1
P. 184 - juillet 2014 Retour au numéro
Article précédent
- Real Life Clinic Visits Do Not Match the Ideals of Shared Decision Making
- Ellen A. Lipstein, Cassandra M. Dodds, Maria T. Britto
- Obliterative Portal Venopathy: A Study of 48 Children
- Stéphanie Franchi-Abella, Monique Fabre, Emmanuel Mselati, Marise Elia De Marsillac, Mohamed Bayari, Danièle Pariente, Emmanuel Jacquemin, Olivier Bernard
Bienvenue sur EM-consulte, la référence des professionnels de santé.
L’accès au texte intégral de cet article nécessite un abonnement.
Déjà abonné à cette revue ?