C1QTNF3 and obesity due to melanocortin 4 receptor deficiency: In human, circulating CTRP3 level is lower in obesity and negatively correlated with insulin resistance.65 Glucagon‐like peptide‐1 receptor agonist Exendin‐4 was shown to increase CTRP3 expression in vitro.66 Metformin treatment was also found to elevate serum CTRP3 levels in women with polycystic ovarian disease.67