Tohoku J. Exp. Med., 2004, 204(1)

Effects of Ethanol on the Induction of Uncoupling Protein-1 (UCP1) mRNA in the Mouse Brown Adipose Tissue

KANJI YOSHIMOTO, MASAHIRO YASUHARA, SETSUO KOMURA, YUKI MISUMI, YUKI UCHIYAMA, AKINORI KOGURE,¹ CHIZUKO HIOKI,¹ YASUO WAKABAYASHI,² YOSHIKO SATOMI,² AKIRA NISHIMURA,³ FUMIHIKO FUKUDA, MASAFUMI HORI, CHIHIRO YOKOYAMA⁴ and TOSHIHIDE YOSHIDA¹

Department of Legal Medicine, ¹Department of Endocrinology, Diabetes and Metabolism, ²Department of Biochemistry, ³Department of Pediatrics, and ⁴Department of Psychiatry, Kyoto Prefectural University of Medicine, Kyoto 602-8566

Expression of uncoupling protein-1 (UCP1) is increased by cold acclimation and overfeeding, and reduced in fasting and genetic obesity. It is known that the mitochondrial UCP1 in the brown adipose tissue (BAT) is an important key molecule for non-shivering thermogenesis. On the other hand, ethanol (EtOH) alters thermoregulation in humans and laboratory animals. However, the relationship between EtOH intake and UCP1 expression is not yet clear. Accordingly, the present study employed the technique of real-time quantitative polymerase-chain reaction (PCR) to investigate the effects of EtOH (0.5 or 2.0 g/kg) on the expression of UCP1 mRNA in the mouse BAT. Control mice were injected with the same volume of physiological saline intraperitoneally (IP). IP injection of EtOH (0.5 g/kg) caused a decrease and an increase of the expression of BAT UCP1 mRNA at 1 and 4 hours, respectively. Treatment with EtOH (2.0 g/kg) caused an increases of the expression of BAT UCP1 mRNA at both 2 and 4 hours. BAT UCP1 mRNA levels in both groups increased at 4 hours after EtOH administration. The levels of UCP1 mRNA returned to the control levels by 8 hours after EtOH administration. The expression of BAT UCP1 mRNA was upregulated following EtOH administration, although a lower dose of EtOH initially reduced the expression of UCP1 mRNA in BAT. These findings suggest that EtOH-induced UCP1 mRNA expression in BAT reflects an alteration of the set point of thermogenesis.

keywords —— uncoupling protein; ethanol; brown adipose tissue; mouse

© 2004 Tohoku University Medical Press

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Address for reprints: Kanji Yoshimoto, Ph.D., Department of Legal Medicine, Kyoto Prefectural University of Medicine, Kawaramachi, Kamigyo-ku, Kyoto 602-8566, Japan.

e-mail: kyoshimo@koto.kpu-m.ac.jp