ISSN:
1573-6903
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract A gas chromatographic-mass spectrometric method was developed for analyzing phenylalanine and tyrosine (Tyr) in plasma and brain. With this procedure, we were able to show that18O2 is incorporated into Tyr in vivo and that the presence of18O-Tyr in plasma is a relative measure of phenylalanine hydroxylating activity. Treatment withp-chlorophenylalanine decreases the18O incorporation into Tyr. Because of the simplicity of the procedure and its easy adaptability to human studies, the incorporation of18O2 into endogenous constituents might serve as a useful diagnostic procedure for some metabolic disorders, such as phenylketonuria. These results also indicate that labeling with18O cannot be used to measure the turnover rate of brain catecholamines as previously proposed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00963778
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