(A–B) PdgfraCre-ERT2; Rosa26RRFP (PDGFRα-RFP) mice were administered TM (A) at postnatal day (P) 10 or (B) at P60. IGW, PGW, and BATs were examined for direct RFP fluorescence and RFP IHC staining after 3 days (pulse). Scale = 200 μm. (C) PDGFRα-RFP mice were administered TM at P60 and fed chow or HFD until P180. IGW, PGW, and BATs were examined for direct RFP fluorescence and RFP IHC staining at P180 (chase). Scale = 100 μm and 200 μm. (D) Quantification of RFP+ adipocytes observed in randomly chosen 10× magnification fields from IGW, PGW, and BAT sections. (E) Confocal immunofluorescence image of a representative IGW section from animals treated with TZD. Sections were stained with anti-RFP (red) and anti-perilipin (green) antibodies and counterstained with DAPI (blue; nuclei). Scale = 200 μm.