Effect of high-fat diet, surrounding temperature, and enterostatin on uncoupling protein gene expression

Nonshivering thermogenesis induced in brown adipose tissue (BAT) during hig h-fat feeding is mediated through uncoupling protein 1 (UCP1). UCP2 is a re cently identified homologue found in many tissues. To determine the role of UCP1 and UCP2 in thermoregulation and energy balance, we investigated the long-term effect of high-fat feeding on mRNA levels in mice at two differen t ambient temperatures. We also treated mice with the anorectic peptide ent erostatin and compared mRNA levels in BAT, white adipose tissue (WAT), stom ach, and duodenum. Here, we report that high-fat feeding at 23 degrees C in creased UCP1 and UCP2 levels in BAT four- and threefold, respectively, and increased UCP2 levels fourfold in WAT. However, at 29 degrees C, UCP1 decre ased, whereas UCP2 remained unchanged in BAT and increased twofold in WAT. Enterostatin increased UCP1 and decreased UCP2 mRNA in BAT. In stomach and duodenum, high-fat feeding decreased UCP2 mRNA, whereas enterostatin increa sed it. Our results suggest that the regulation of uncoupling protein mRNA levels by high-fat feeding is dependent on ambient temperature and that ent erostatin is able to modulate it.