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Effect of Valine on 5-HT-mediated Prolactin Release in Healthy Volunteers, and on Mood in Remitted Depressed Patients

Published online by Cambridge University Press:  02 January 2018

D. J. Williamson
Affiliation:
Psychopharmacology Research Unit, Littlemore Hospital, Oxford
S. F. B. McTavish
Affiliation:
Psychopharmacology Research Unit, Littlemore Hospital, Oxford
S. B. G. Park
Affiliation:
Psychopharmacology Research Unit, Littlemore Hospital, Oxford
P. J. Cowen*
Affiliation:
Psychopharmacology Research Unit, Littlemore Hospital, Oxford
*
Dr Cowen, University Department of Psychiatry, Littlemore Hospital, Oxford OX4 4XN

Abstract

Background

Animal experimental studies suggest that the amino acid valine may decrease brain serotonin (5-HT) function by inhibiting the transport of the 5-HT precursor, L-tryptophan, across the blood barrier. The aim of the present study was to assess whether valine could decrease brain 5-HT function in healthy subjects and provoke symptomatic relapse in recently remitted depressed patients taking antidepressant drug treatment.

Method

We studied the effect of valine (30 g) on the prolactin (PRL) response to the 5-HT releasing agent, d-fenfluramine, in healthy male subjects and on the mood of 12 remitted depressed patients taking either selective serotonin re-uptake inhibitors (n = 10) or lithium and amitriptyline (n = 2).

Results

Valine significantly lowered the PRL response to d-fenfluramine in healthy subjects. In the remitted depressives, valine caused a mild but detectable lowering of mood on a number of measures but only one patient experienced a significant relapse in mood.

Conclusions

Valine administration may decrease brain 5-HT neurotransmission in humans. This effect could explain the mild increase in depressive symptoms in patients taking 5-HT-potentiating drugs.

Type
Papers
Copyright
Copyright © 1995 The Royal College of Psychiatrists 

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