The WAT of the aP2-Cre/L-PGDSflox/flox mice were smaller in size than the control L-PGDSflox/flox mice (Fig. 4d,e), suggesting that adipose L-PGDS and PGD2 are associated with the enhancement of obesity, together with the enlargement of adipose cells. This evidence concerns the gene FABP4 and obesity due to melanocortin 4 receptor deficiency.