Updated project metadata. To analyse the peptidomics of mouse enteroendocrine cells (EECs) and human gastrointestinal (GI) tissue and identify novel gut derived peptides. High resolution nano-flow liquid chromatography mass spectrometry (LCMS) was performed on (i) flow-cytometry purified NeuroD1 positive cells from mouse and homogenised human intestinal biopsies, (ii) supernatants from primary murine intestinal cultures, (iii) intestinal homogenates from mice fed high fat diet. Candidate bioactive peptides were selected on the basis of species conservation, high expression/biosynthesis in EECs and evidence of regulated secretion in vitro. Candidate novel gut-derived peptides were chronically administered to mice to assess effects on food intake and glucose tolerance.