Ethanol metabolism in ALDH2 knockout mice – Blood acetate levels Ameno Kiyoshi a, * , Wang Weihuan a , Jamal Mostofa a , Kumihashi Mitsuru a , Isse Toyoshi b , Kawamoto Toshihiro b , Kitagawa Kyoko c , Nakayama Keiichi d , Ijiri Iwao a , Kinoshita Hiroshi a a Department of Forensic Medicine, Faculty of Medicine, Kagawa University, 1750-1, Ikenobe, Miki, Kita, Kagawa 761-0793, Japan b Department of Environmental Health, University of Occupational and Environmental Health, Japan c Department of Biochemistry, Hamamatsu University, School of Medicine, Japan d Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyusyu University, Japan article info Article history: Received 12 December 2008 Received in revised form 19 January 2009 Accepted 2 February 2009 Available online 7 April 2009 Keywords: ALDH2 KO mice Ethanol Acetaldehyde Acetate Metabolism abstract We described here blood acetate levels in aldehyde dehydrogenase 2 knockout (ALDH2 KO) male mice based on C57BL/6 J strain after ethanol (EtOH) dosing (2 g/kg). Blood samples were collected at 30, 60, 90, 120 180, and 240 min after decapitation, and then EtOH, acetaldehyde (AcH) and acetate were determined by head-space gas chromatography. We found that blood acetate levels in ALDH2 KO mice were slightly lower than those in wild type (WT), whereas EtOH and AcH levels in ALDH2 KO were significantly higher than those in WT. These observations indicate that high EtOH, AcH and low acetate in the blood of ALDH2 KO are due to the deficient effect of ALDH2 enzyme activity. Ó 2009 Elsevier Ireland Ltd. All rights reserved. 1. Introduction Ethanol (EtOH) is metabolized to acetaldehyde (AcH) by several enzymes such as aldehyde dehydrogenase (ADH), MEOS system involving CYP2E1 and catalase, and then to acetate by aldehyde dehydrogenase (ALDH) [1]. The acetate formed in the liver enters in the blood and is converted rapidly to CO 2 and H 2 O, mainly in peripheral tissues [2]. It is well-known that acetate, the second metabolite of EtOH, is increased in the blood after EtOH consump- tion [3]. It has also been reported that a detectable level of blood ace- tate (30.6–60.1 lM) was found in healthy human subjects [4]. Acetate has been shown to produce some physiological actions such as elevation of portal blood flow caused by increased intes- tinal blood flow, reduction of locomotor activity, alterations of CNS function [3]. Moreover, acetate acts as a precursor of some cholesterols [5]. Kawamoto and his groups are recently produced ALDH2 KO mice based on C57BL/6J as a human model of ALDH2 deficiency [6]. They have been reported the differences of EtOH metabolism in ALDH2 KO mice, which include EtOH consumption and kinetics, and AcH accumulation [7]. Until now, no study has been conducted to quantify acetate levels in the blood of ALDH2 KO mice. We, therefore, focused blood EtOH, AcH and acetate levels and their comparisons in ALDH2 KO and wild type (WT) mice after EtOH dosing. 2. Materials and methods Male C57BL/6 J ALDH KO mice (7–8 weeks old) were bred at the animal building of Kagawa University. Male C57BL/6 J WT mice were obtained from CLEA-Japan (Tokyo). Mice were main- tained in a temperature-controlled colony room with a 12-h light–dark cycle (07:00–19:00 light on). All procedures were approved by the Kagawa University Animal Investigation Committee. Animals were sacrificed at 30, 60, 90, 120, 180 and 240 min after intraperitoneal (i.p.) injection of 2.0 g/kg EtOH (20%, v/v). The quantitation of EtOH, AcH and acetate was performed by a head-space GC method as described previously [8,9]. Elimination rate constant of blood EtOH were calculated according to the TEXT [10]. 3. Statistical analysis All data were statistically analyzed using the statistical pro- gram StatView (J-4.5), and the results are expressed as the mean ± SD. The level of significance of the post hoc tests was set at P < 0.05. 1344-6223/$ - see front matter Ó 2009 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.legalmed.2009.02.043 * Corresponding author. Tel.: +81 87 891 2140; fax: +81 87 891 2141. E-mail address: amenok@kms.ac.jp (A. Kiyoshi). Legal Medicine 11 (2009) S413–S415 Contents lists available at ScienceDirect Legal Medicine journal homepage: www.elsevier.com/locate/legalmed