C1QTNF9 and obesity due to melanocortin 4 receptor deficiency: Previous studies have shown that in AMI model or diet-induced obesity mice, overexpression of CTRP9 enhances AMPK activation, while the knockout of CTRP9 reduced AMPK activation (Kambara et al. 2015; Peterson et al. 2013; Wei et al. 2014).