IGFBP2 and obesity due to melanocortin 4 receptor deficiency: In addition to the significant differences observed in serum adipokines, fasting glucose levels, insulin levels, and glucose tolerance, obesity was also associated with elevated serum levels of IGF-1, IGF-1/IGFBP2, and IGF-1/IGFBP3 in HFD-Obese mice (Table 1).