PTGS2 and obesity due to melanocortin 4 receptor deficiency: In relation to oxylipin metabolism, the expression of the gene encoding PTGS2 significantly increased by 2.7-fold in scWAT from individuals living with obesity in response to 12-week fish oil intervention, but this was not accompanied by a change in the activity of COX-2 in these individuals or in normal weight individuals (P ≥ 0.166, Paired T-test, data not shown).