We obtained Ucp1-luciferase mice from the laboratory of Dr. Shingo Kajimura (University of California, San Francisco) [15 (link)]. Briefly, 150 mg/kg of D-Luciferin potassium salt (GoldBio, St. Louis, MO, USA) was injected into WT and Tph1 FKO with Ucp1-luciferase fed SCD or HFD. Fifteen minutes post-injection, we detected luciferase activity using IVIS Lumina S5, using the Living Image software (PerkinElmer, Waltham, MA, USA) to setup (autoexposure), analyze, and organize data.