Normal values and age-dependent changes in GTP cyclohydrolase I activity in stimulated mononuclear blood cells measured by high-performance liquid chromatography
M. Hibiya et al., Normal values and age-dependent changes in GTP cyclohydrolase I activity in stimulated mononuclear blood cells measured by high-performance liquid chromatography, J CHROMAT B, 740(1), 2000, pp. 35-42
GTP cyclohydrolase I (GCH1) activity in phytohemaglutinin (PHA)-stimulated
mononuclear blood cells (MBCs) is a useful clinical marker for diagnosis of
tetrahydrobiopterin (BH4)-related genetic disorders such as recessively in
herited GCH1 deficiency and dominantly inherited dopa-responsive dystonia (
Segawa's disease). Since the assay is complex, including isolation of MBCs
from blood, stimulation of MBCs by PHA under culture, isolation of the prot
ein fraction from the PHA-stimulated MBCs, and the subsequent activity meas
urement, the reproducibility is problematic in its application to clinical
study. We established a sensitive and reproducible method by high-performan
ce liquid chromatography with fluorescence detection for clinical assay of
GCH1 in PHA-stimulated MBCs, and measured the normal values of 91 healthy m
ales and females of various ages (1-74 years). The mean normal values were
19.1+/-0.9 pmol/mg protein per h (mean+/-S.E., n=91). There were no signifi
cant differences between males and females. The activity tends to be higher
in the first decade and to be decreased from the second to third decade an
d becomes almost stable from the third decade. (C) 2000 Elsevier Science B.
V. All rights reserved.