As far as we know, two previous studies in humans, with small sample size (n = 39–40), examined protein or gene expression of the IGF1, IGF2, IGFBP3, INSR, IGF1R and downstream targets IRS1, IRS2 and mTOR in women with or without type 2 diabetes [34, 35]. This evidence concerns the gene IRS2 and type 2 diabetes mellitus.