UCP1 and serum lipopolysaccharide activity: For example, Eskilsson et al. observed no elevation in the expression of Ucp1 or Pgc1a mRNA, and no noticeable changes in BAT weight or TG levels following the administration of LPS (7), but they assessed UCP-1 expression only 4 hours after LPS injection and analyzed weight of BAT only 6 hours after the onset of endotoxemia.