A. ALLAMEH A, NIKSERESHT M, KHEYRDOOSH F. ROLE OF CYTOSOLIC GL U TATHIONE S- T RANSFERASES IN PRO TEC TION AGAINS T ACE TAMINOPHEN-INDUCED LIPID PEROXIDATION IN WEANLING RATS. Med J Islam Repub Iran 1999; 13 (3) :213-217
URL:
http://mjiri.iums.ac.ir/article-1-939-en.html
From the Department of Biochemistry, Faculty of Medical Sciences, Tarbiat Modaress University, p.o. Box 141554838, Tehran,I.R.Iran.
Abstract: (4945 Views)
Resistance of the weanling rat to acetaminophen (AP AP)-induced hepatotoxicity
is manifested with regard to a surge in APAP-glutathione (OSH) conjugate
formation in the liver [Allameh et al. Mech Aging Dev 95(1997)71]. The present
study was conducted to assess the role of this detoxification pathway in APAPinduced
lipid per6xidationin the liver. Lipid peroxidation measured as thiobarbituric
acid reactive substances (TBARS) in rat liver homogenate was observed to be
increased due to a decrease in hepatic cellular GSH concentration. Cellular GSH
content was relatively lower in growing liver and further decreased in rats treated
with either GSH-depleting agents or APAP, whereas adult animals under APAP
treatment suffered significantly less depletion of GSH. AP AP injection to weanling
rats pre-treated with diethylmaleate (DEM) aggravated lipid peroxidation.
Administration of a single large dose of APAP (500 mg/kg b. w.) to weanling rats,
3 h before sacrifice, which caused 46% GSH depletion, resulted in a 25% increase
in lipid peroxidation. Pre-treatment of growing rats with DEM, 30 min before
APAP, caused about 70% depletion in GSH content as a result of which there was
a further increase (approx. 1.6 fold) in lipid peroxide formation (control: 37.40
experimental: 60.76 nmol malondialdehyde formation/g tissue). GSH S-transferase
activity is not necessarily a determinant of APAP toxicity in adult animals. Unlike
adults, in growing tissues the enzyme activity is indu.ced single overdose of APAP. When these data are discussed in relation to our earlier
study, it could be concluded that APAP-dependent induction of GSHS-transferases
is responsible for increased APAP-GSH conjugate formation which facilitates
inactivation of NAPQI as well as other toxic metabolites of lipid peroxidation.