Chronic treatment with ATRA does not increase UCP1 expression in differentiating SGBS, hMADS and primary human adipocytes. Total RNA was harvested at the indicated days (day 12 in panel A and B) and analyzed by RT-qPCR. Relative mRNA expression levels of FABP4, UCP1 and RARβ were determined by normalization to TBP. ATRA was supplemented to differentiating SGBS cells (A), hMADS cells (B) and primary human white preadipocytes (HPrAD) (C) from day −2 to day 12 at the concentrations indicated. (D) Protein levels of UCP1 with GAPDH used as a loading control in SGBS and hMADS adipocytes. (A-C) Data represents mean + SEM (n = 3). *, p < 0.05 versus vehicle-treated cells.