A key factor in peripheral androgen metabolism is aldo-keto reductase type 1C3(AKR1C3), which converts A4 to T. AKR1C3 is highly expressed in adipose tissue(28), and its expression in subcutaneousadipose tissue is increased not only in subjects with simple obesity (29) but also in women with PCOS (30). This evidence concerns the gene AKR1C3 and obesity due to melanocortin 4 receptor deficiency.