Le tissu adipeux brun humain | Brown adipose tissue in humans
2012
Ricquier, Daniel
The mammalian brown adipose tissue is made of adipose depots formed by specific adipocytes, the brown adipocytes, morphologically and functionally distinct from white adipocytes. Most studies on brown adipose tissue were carried out in rodents and hibernators and demonstrated its major role in adaptive thermogenesis and the control of body temperature. Thermogenesis in brown adipocytes results from a very high number of mitochondria exhibiting a unique capacity to respire independently of their capacity to synthesise ATP. This uncoupling between respiration and ADP phosphorylation is induced, in a physiologically-regulated manner, by UCP1, a proton carrier uniquely present in the inner membrane of brown fat mitochondria. Brown adipose tissue is present in newborn babies, but it was accepted, contrary to the conclusion of data presented around 1980–1986, that this tissue does not exist in human adults. Very recent data presented by oncologists and expert in PET-Scan imaging provided convincing data in favor of the presence of abundant brown adipose tissue in adult humans. These data clearly establish that brown adipose tissue is active in maintenance of body temperature in individuals exposed to the cold. They also re-open the question of a significant role for brown adipose tissue in energy balance in man.
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