Moreover, exposure to these chemicals promotes the development of obesity through multiple pathways, including (1) upregulating the expression of a liver lipogenic enzyme which has great obesogenic effects [69]; (2) suppressing the mRNA expression of gene encoding insulin leading to poor insulin production, which results in obesity via inducing hyperglycemia [70]; (3) disrupting triacylglycerol metabolism resulting in obesity [71]; (4) significantly reducing the mRNA levels of lipogenic transcription factor srebp1 and increasing that of fatty acid synthetase [72]. This evidence concerns the gene INS and obesity due to melanocortin 4 receptor deficiency.