II-82 Zdrav Vestn 2007; 76: SUPPL II
NONMITOCHONDRIAL GLUTAMATE DEHYDROGENASE IN SERA
OF ALCOHOLICS
Matej Kravos1, Ivan Malešič2
1 Psychiatric Hospital Ormož, Ormož, Slovenia
2 Faculty of Pharmacy, University of Ljubljana, Ljubljana, Slovenia; mk4@siol.net
Background Glutamate dehydrogenase (GLDH) is to be found almost exclusively in mitochondrial ma-
trix of all tissues except erythrocytes. GLDH occurs in two catalytically active forms, deter-
mined as soluble (thermo stable) and particulate (thermo labile). The more recent data
show it also occurs in rough endoplasmic reticulum in thermo stable form. The housekeep-
ing GLDH (thermo stable) and nerve tissue-specific (thermo labile) could be found in the
brain. The GLUD1 gene (housekeeping GLDH) is localised on human chromosome 10 and
is expressed as a thermo stable isoprotein, while GLUD2 (nerve tissue-specific) is localised
on human chromosome X and is expressed as thermo labile isoprotein. The increased sera
GLDH activity is believed to be exclusively the result of liver damage caused by mitochon-
drial injury at cell necrosis. We wanted to examine, whether GLDH detected in sera of
alcoholics may be exclusively derived from hepatocyte mitochondria or even from rough
endoplasmic reticulum.
Patients and GLDH activity was assessed in 205 patients admitted to hospital for treatment of alcohol
methods dependence.
Results In sera of alcoholics we found on average 32.4 % thermo-stable and 67.6 % thermo-labile
GLDH. 62.93 % (129) among all of them had more than 20 % thermo stable GLDH, in
59.06 % cases it was over 20th percentile. The distribution of both isoproteins was uneven.
What means that almost one third of serum GLDH originates from rough endoplasmic
reticulum and the rest from mitochondria. This is an absolutely new finding.
There was a moderate correlation between thermo stable GLDH in rough endoplasmic
reticulum and GGT inducted by elevated CYP2E1 activity.