NPY4R and diabetes mellitus: Although clinical application of NPY1R-specific compounds for diabetes is limited by off-target side-effects including increased appetite [25] and induction of hypertension [26], which is not the case for NPY4R, the fact that the intracellular signalling cascades triggered following NPY1R or NPY4R activation are comparable [27] supports the likely positive effects of (P3)PP on islet cell lineage.