UCP1 and hydrops fetalis: Next, the expression of UCP1 was detected using an immunohistochemistry test, the results of which showed that the abdominal subcutaneous adipose tissues of HF-fed rats had downregulation of BAT-specific UCP1, compared to that of NF-fed rats (Figure 1f and g, P < 0.001), while either Met or L-car resisted that reduction of BAT-specific UCP1 expression (Figure 1f and g, P < 0.001).