Relationship between glutamate, GOT and GPT levels in maternal and fetal blood: a potential mechanism for fetal neuroprotection.
BACKGROUND
Excess glutamate in the brain is thought to be implicated in the pathophysiology of fetal anoxic brain injury, yet little is known about the mechanisms by which glutamate is regulated in the fetal brain. This study examines whether there are differences between maternal and fetal glutamate concentrations, and whether a correlation between them exists.


METHODS
10 ml of venous blood was extracted from 87 full-term (>37 weeks gestation) pregnant women in active labor. Immediately after delivery of the neonate, 10 ml of blood from the umbilical artery and vein was extracted. Samples were analyzed for levels of glutamate, glutamate-oxaloacetate transaminase (GOT), and glutamate pyruvate transaminase (GPT).


RESULTS
Fetal blood glutamate concentrations in both the umbilical artery and vein were found to be significantly higher than maternal blood (p<0.001). Similarly, fetal serum GOT levels in the umbilical artery and vein were found to be significantly higher than maternal GOT levels (p<0.001). The difference in GPT levels between maternal and fetal serum was not statistically significant. There was no difference in fetal glutamate, GOT or GPT between the umbilical artery and vein. There was an association observed between glutamate levels in maternal blood and glutamate levels in both venous (R=0.32, p<0.01) and arterial (R=0.33, p<0.05) fetal blood.


CONCLUSIONS
This study demonstrated that higher baseline concentrations of blood glutamate are present in fetal blood compared with maternal blood, and this was associated with elevated GOT, but not GPT levels. An association was observed between maternal and fetal blood glutamate levels.
Department of Anesthesiology and Critical Care, Soroka Medical Center, Ben Gurion University of the Negev, Faculty of Health Sciences, Beer Sheva, Israel. zlotnika@bgu.ac.il
Alexander
A
Zlotnik
Svetlana
S
Tsesis
Benjamin Fredrick
BF
Gruenbaum
Sharon
S
Ohayon
Shaun Evan
SE
Gruenbaum
Matthew
M
Boyko
Eyal
E
Sheiner
Evgeny
E
Brotfain
Yoram
Y
Shapira
Vivian Itzhak
VI
Teichberg
D000328:Adult; D000410:Alanine Transaminase / Q000097:blood*; D001219:Aspartate Aminotransferases / Q000097:blood*; D004796:Clinical Enzyme Tests; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D005316:Fetal Distress / Q000097:blood; D018698:Glutamic Acid / Q000097:blood*; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D011247:Pregnancy
D018698:Glutamic Acid; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase