Since protein levels of DRD1 and DRD2 generally did not follow mRNA expression patterns, we performed correlation analyses between DRD1 and DRD2 protein expression and obesity and hyperglycemia in subjects without T2D and with NGT or IFG, and T2D (cohort 1), respectively (Fig. 4). Here, DRD2 is linked to type 2 diabetes mellitus.