RAT UNCOUPLING PROTEIN-2 (UCP2) - EXPRESSION IN OBESE VENTROMEDIAL HYPOTHALAMUS (VMH)-LESIONED ANIMALS

BACKGROUND: The family of uncoupling proteins is thought to play an im portant role in the regulation of energy metabolism by uncoupling the respiratory chain reactions from ATP synthesis. The recently discovere d uncoupling protein 2 (UCP2) is upregulated in genetically obese rode nt models and during long term high fat feeding. AIM: We have examined the UCP2 mRNA levels in liver, heart and white adipose tissue (WAT) o f obese ventromedial hypothalamus (VMH)-lesioned rats, during the dyna mic and the early stage of the static phase of obesity, before the app earance of most of the metabolic perturbations associated with long te rm established obesity. RESULTS: The amount of UCP2 mRNA was not incre ased in any tissue of VMH-lesioned rats relative to control animals du ring the dynamic phase nor during the early static phase of obesity. C ONCLUSION: These results indicate that in the rat, obesity does not ne cessarily lead to an increase in UCP2 expression and suggest that the up-regulation of UCP2 described in other models may be secondary to me tabolic perturbations, rather than to a direct adaptative response to the increased adipose tissue content of the organism.