IGFBP3 and obesity due to melanocortin 4 receptor deficiency: Nevertheless, our data demonstrate that IGFBP-3 does not affect insulin-induced glucose uptake under normal conditions (Figure 3G) A recent study shows that diet-induced obese rats show a downregulation of IGFBP-3 expression in mesenteric fat when compared to their lean counterparts, suggesting that IGFBP-3 may have a protective effect against obesity [36].