Altered antioxidant enzyme activities in children with a serious adverse experience related to valproic acid therapy.
Specific oxidative metabolites of valproic acid (VPA) have been associated with the clinically defined toxicity of the drug. To investigate the role of enzymatic detoxification in clinical toxicity, we compared activities of five antioxidant enzymes in 15 patients with a serious adverse experience (SAE) related to VPA therapy, to enzyme activities measured in 35 patients with good clinical tolerance of VPA, and 50 healthy, age-matched subjects. These enzymes included glutathione peroxidase (GSH-Px), glutathione reductase (GSSG-R), glutathione transferase, superoxide dismutase, and catalase in erythrocytes; and GSH-Px in plasma. We also determined levels of Se, Cu, and Zn, trace elemental cofactors for these enzymes, in plasma from each individual. In patients with a VPA-associated SAE, GSH-Px was significantly depressed and GSSG-R was significantly elevated relative to values for the other groups. Selenium and zinc concentrations were lower in SAE patients than in controls. These findings may indicate a role for selenium dependent antioxidant activity in individual susceptibility to an SAE related to VPA therapy.
Graf
W D
WD
Department of Pediatrics, University of Washington, Seattle, USA.
Oleinik
O E
OE
Glauser
T A
TA
Maertens
P
P
Eder
D N
DN
Pippenger
C E
CE
D000704:Analysis of Variance; D000975:Antioxidants / Q000032:analysis; D001219:Aspartate Aminotransferases / Q000097:blood / Q000187:drug effects; D002648:Child; D002653:Child Behavior Disorders / Q000097:blood / Q000139:chemically induced / Q000201:enzymology; D002675:Child, Preschool; D004791:Enzyme Inhibitors / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D008297:Male; D018384:Oxidative Stress / Q000187:drug effects* / Q000502:physiology; D014131:Trace Elements / Q000097:blood / Q000172:deficiency; D014635:Valproic Acid / Q000008:administration & dosage / Q000009:adverse effects*
D000975:Antioxidants; D004791:Enzyme Inhibitors; D014131:Trace Elements; D014635:Valproic Acid; D001219:Aspartate Aminotransferases