Tyrosine transport is regulated differently in patients with schizophrenia.
Schizophr Res
; 40(1): 37-42, 1999 Nov 09.
Article
in En
| MEDLINE
| ID: mdl-10541005
ABSTRACT
Previous PET studies of tyrosine transport have suggested that the transport of tyrosine from blood to brain compartment is not dependent on its plasma concentration in patients with schizophrenia. In order to examine this relationship, the transport constant (K1) of tyrosine was determined in five patients with schizophrenia and five normals. L-[1-11C]Tyrosine was injected i.v. and arterial blood samples were taken during PET scanning. The tyrosine transport was assessed during baseline conditions and after oral administration of L-tyrosine at a dose (175 mg/kg) that significantly elevated the plasma levels. K1 was determined from tracer kinetic modelling. The transport rate dropped in the normals after tyrosine loading, which is consistent with the prevailing notion that the brain transport system for neutral amino acids works close to saturation, whereas it was virtually unchanged in the schizophrenics. The results demonstrated that tyrosine transport was not saturated in the patients with schizophrenia and thus could lead to elevated brain concentrations of tyrosine.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Schizophrenia
/
Tyrosine
/
Brain
Limits:
Humans
Language:
En
Journal:
Schizophr Res
Journal subject:
PSIQUIATRIA
Year:
1999
Document type:
Article
Affiliation country:
Suecia