Volume 103, Issue 1 pp. 36-42

Deficiency in Cytosolic Malic Enzyme Does Not Increase Acetaminophen-Induced Hepato-Toxicity

Su Qian

Su Qian

Department of Metabolic Disorders, Merck Research Laboratories, Rahway, NJ, USA

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Sheena Mumick

Sheena Mumick

Department of Metabolic Disorders, Merck Research Laboratories, Rahway, NJ, USA

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Peter Nizner

Peter Nizner

Department of Metabolic Disorders, Merck Research Laboratories, Rahway, NJ, USA

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Michael R. Tota

Michael R. Tota

Department of Metabolic Disorders, Merck Research Laboratories, Rahway, NJ, USA

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Joseph Menetski

Joseph Menetski

Department of Metabolic Disorders, Merck Research Laboratories, Rahway, NJ, USA

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Marc L. Reitman

Marc L. Reitman

Department of Metabolic Disorders, Merck Research Laboratories, Rahway, NJ, USA

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Douglas J. MacNeil

Douglas J. MacNeil

Department of Metabolic Disorders, Merck Research Laboratories, Rahway, NJ, USA

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First published: 28 June 2008
Citations: 7
Author for correspondence: Su Qian, Department of Metabolic Disorders, Merck Research Laboratories, P.O. Box 2000, RY80M-213, Rahway, NJ 07065, USA (fax 732-594-6708, e-mail [email protected]).

Abstract

Abstract:  Cytosolic malic enzyme (ME-1) is a nicotinamide adenine dinucleotide phosphate (NADP)-dependent enzyme that generates NADPH. The activity of this enzyme, the reversible oxidative decarboxylation of malate to yield pyruvate, links glycolytic pathway to citric acid cycle. The high level of ME-1 expression in liver, and its involvement in NADPH production, suggests reduced ME-1 activity might compromise hepatic production of reduced glutathione (GSH) by the NADPH-dependent enzyme glutathione reductase, and hence affect xenobiotic detoxification. The role of ME-1 in liver detoxification was evaluated in Mod1 deficient mice (mod1−/–) by evaluating their sensitivity to acetaminophen-induced liver injury. The results show that mod1−/– mice are not more sensitive to acetaminophen hepato-toxicity. Although GSH levels were initially depleted more in the mod1−/– liver than in wild-type controls, the GSH levels recovered quickly. In conclusion, our data indicate that ME-1 deficiency does not adversely affect GSH-dependent detoxification.

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