Jpn. J. Pharmacol. 77 (3), 247-249 (1998)

The Effect of Acute Cold Exposure and Norepinephrine on Uncoupling Protein Gene Expression in Brown Adipose Tissue of Monosodium Glutamate-Obese Mice

Fujiko Tsukahara, Yoko Uchida, Ken-ichi Ohba, Akira Ogawa, Toshimasa Yoshioka and Takamura Muraki

Department of Pharmacology, Tokyo Women's Medical University, School of Medicine, 8-1, Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan

Abstract: Abnormal regulation of mitochondrial uncoupling protein (UCP) gene expression was studied in brown adipose tissue (BAT) of monosodium glutamate (MSG)-induced obese mice. UCP mRNA levels in control mice increased markedly after acute cold exposure; however, MSG-obese mice showed an impaired response. In contrast, an injection of norepinephrine (NE) induced a comparable increase in UCP mRNA levels in control and MSG-obese mice. These results suggest that the impairment in the cold-induced increase in UCP mRNA is due to a deficient sympathetic input to BAT and/or to a diminished response of BAT to endogenous NE, which constitutes the mechanism of impaired thermoregulation in obese mice in a cold environment.

Keywords: Monosodium glutamate, Brown adipose tissue, Uncoupling protein

Copyrightę The Japanese Pharmacological Society 1998

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