Further testing for isoform specificity, using p110α and p110δ discriminating compounds, revealed that the anti-obesity effect was particularly prominent upon inhibition of p110α, the principal insulin activated isoform, although inhibition of p110δ did contribute to the overall effect (Lopez-Guadamillas et al. 2016). This evidence concerns the gene INS and obesity due to melanocortin 4 receptor deficiency.