Figure 5. 1,25(OH)₂D₃ acts during the early stages of brown adipogenesis.

C3H10T1/2 cells were differentiated for 7 days; 100 pM 1,25(OH)₂D₃ or the vehicle control (EtOH) was added from day zero to 2 or from days 2 to 7. (A) mRNA levels of Ucp1, Fabp4, and Plin on day 7 (0–2 days; n = 3, 2–7 days; n = 4). 1,25(OH)₂D₃ (1,25D₃) (B) UCP1 protein expression on day 7. (C) Expression of brown adipogenesis-related transcription factors. C3H10T1/2 cells were differentiated in the absence or presence of 100 pM 1,25(OH)₂D₃. mRNA levels of Prdm16, Pgc1α, Pparα, Pparγ, Cidea, and Cebpa were measured 48 h after the initiation of differentiation (n = 4). (D) Expression of adipogenesis-related transcription factors during the early stages of differentiation. C3H10T1/2 cells were differentiated in the absence or presence of 100 pM 1,25(OH)₂D₃ 12 h after differentiation initiation, and the mRNA levels of Pparγ, Cebpa, Cebpb, and Cebpd were measured using quantitative reverse transcription-polymerase chain reaction (n = 3). (E) Effect of 1,25(OH)₂D₃ on the stimulation of Ucp1 promoter activity (n = 4). Data are shown as mean ± standard error of the mean. * p < 0.05, ** p < 0.01, *** p < 0.001 versus control (0 pM).