P2X7 is present in β-cells, and it is down-regulated in T2D. In human islets, P2X7 seems to be involved in secretion of insulin (165). The P2X7 KO mice have lower β-cell mass, impaired glucose tolerance and defective insulin and interleukin secretion (172). This evidence concerns the gene P2RX7 and type 2 diabetes mellitus.