Considering the decrease in GABA (GAD67) (Figure 2B) in the striatum of middle-aged GK rats, which could indicate the reduction in overall inhibitory activity in that structure, we could speculate that the increase in PV-interneuron size could indicate an increased connectivity or inhibitory activity of PV-interneurons as a compensatory mechanism to balance the likely overall decrease in GABAergic inhibitory signalling under T2D. This evidence concerns the gene GAD1 and type 2 diabetes mellitus.