Neuropeptide Y is synthesized by mouse pancreatic beta cells.

<p>(A). A small cluster of pancreatic cells in which some insulin-ir (beta) cells are also NPY-ir (arrow indicates one example). Also present is a beta cell that is not NPY-ir (arrow head). (B). Single confocal slice through an insulin-ir cell that was also NPY-ir. Indicated are two puncta that are co-stained for NPY and insulin (arrows). (C). Quantification of the fluorescent signal from individual puncta. ROI's corresponding to single NPY-ir puncta were selected then the corresponding signal in the insulin (red) channel was also measured. Left panel; a plot of fluorescence intensities indicates that there is a positive correlation between the signal in the two channels consistent with the coexpression of NPY and insulin in individual granules (n = 90 granules from 3 cells, R = 0.86). Right panel; the distribution of the punctal signals. (D). Islet cells from a neonatal (P0) NPY knockout animal were co-stained for NPY, insulin, glucagon and somatostatin. NPY-ir was not present in insulin-ir cells (arrow head), while punctate “NPY-ir” was seen in both glucagon- and somatostatin-ir cells (arrows). Thus authentic NPY-ir is only present in beta cells. Scale bars 10 µm (A,D) 5 µm (B).