Termogênese nos Seres Vivos UCP1 e FRIO Mamíferos Tecido Adiposo Branco (WAT) - armazenar energia na forma de gordura Tecido Adiposo Marron (BAT) - dissipação do calor = TERMOGENESE - Importante durante a termogenese não-tremor (nonshivering) observada em mamíferos durante a hibernação, em pequenos roedores expostos ao frio e em recém-nascidos. - UCP1 é a proteína responsável pela termogenese. Consumo de O2 30 % 129 UCP -/- Comparison of body weight, fat mass, and fat-free mass at various temperatures during the adaptation process shows a greater loss of body weight in UCP1 -/- The adaptability of UCP1 -/- mice to the cold depends upon their ability to increase oxygen consumption Reduced triglyceride levels in serum together with increased β-hydroxybutyrate levels suggest increased fatty acid oxidation in both genotypes, but particularly in the UCP1 -/- mice. Reductions in liver glycogen levels especially in cold-adapted UCP 1 -/- mice suggest that glycogen is an important source of fuel for thermogenesis. The elevated thyroid hormones in serum also suggest a role for these hormones in stimulating thermogenesis, particularly in Ucp1 -/- mice. The absence of major changes in either the triglycerides or glycogen of skeletal muscle suggests that muscle metabolism is not a key site for enhanced metabolism to support thermogenesis in either genotype. Freshly collected adipose tissue analyzed histologically and shown to have the expected brown adipocyte morphology. In this study UCP1-deficient mice showed virtually no change in gene expression in muscle but profound changes in white adipose tissues at the morphological, metabolic, and molecular levels.