Brown fat is essential for cold-induced thermogenesis but not for obesity resistance in aP2-Ucp mice

• Published in: American journal of physiology: endocrinology and metabolism Vol. 274; no. 3; pp. E527 - E533
• Main Authors: Stefl, B, Janovska, A, Hodny, Z, Rossmeisl, M, Horakova, M, Syrovy, I, Bemova, J, Bendlova, B, Kopecky, J
• Format: Journal Article
• Language: English
• Published: United States 01.03.1998
• Subjects: Adipose Tissue - physiology; Adipose Tissue, Brown - physiology; ADIPOSE TISSUES; Animals; Body Temperature Regulation - genetics; Body Temperature Regulation - physiology; Body Weight; Carrier Proteins - genetics; Carrier Proteins - physiology; COLD; Cold Temperature; Energy Metabolism; FRIO; FROID; Homozygote; Immunity, Innate - genetics; Ion Channels; Male; Membrane Proteins - genetics; Membrane Proteins - physiology; Membrane Transport Proteins; MICE; Mice, Inbred C57BL; Mice, Transgenic; Mitochondrial Proteins; Obesity - genetics; Obesity - physiopathology; Promoter Regions, Genetic; Proteins - genetics; Proteins - physiology; RATON; SOURIS; TEJIDO ADIPOSO; TERMORREGULACION; THERMOREGULATION; Thyroid Gland - physiology; TISSU ADIPEUX; Transgenes; Uncoupling Protein 1; Uncoupling Protein 2
• ISSN: 0002-9513; 0193-1849; 2163-5773; 1522-1555
• DOI: 10.1152/ajpendo.1998.274.3.E527

Faculty of Sciences, Charles University, 128 00 Prague; Institute of Endocrinology, 116 91 Prague; and Institute of Physiology, Academy of Sciences of the Czech Republic, 142 20 Prague, Czech Republic The role of brown adipose tissue in total energy balance and cold-induced thermogenesis was studied. Mice expressing mitochondrial uncoupling protein 1 (UCP-1) from the fat-specific aP2 gene promoter (heterozygous and homozygous aP2 -Ucp transgenic mice) and their nontransgenic C57BL6/J littermates were used. The transgenic animals are resistant to obesity induced by a high-fat diet, presumably due to ectopic synthesis of UCP-1 in white fat. These animals exhibited atrophy of brown adipose tissue, as indicated by smaller size of brown fat and reduction of its total UCP-1 and DNA contents. Norepinephrine-induced respiration (measured in pentobarbital sodium-anesthetized animals) was decreased proportionally to the dosage of the transgene, and the homozygous (but not heterozygous) transgenic mice exhibited a reduction in their capacity to maintain body temperature in the cold. Our results indicate that the role of brown fat in cold-induced thermogenesis cannot be substituted by increased energy expenditure in other tissues. C57BL/6J mouse strain; uncoupling protein 1; high-fat diet; adipose tissue; mitochondria