Glucagon is a member of a multigene family comprising of Secretin, Vasoactive Intestinal Peptide (VIP), Gastric Inhibitory Peptide (GIP) and others like Glicentin and Oxyntomodulin (OXM), which differs from glucagon by C-terminal octapeptide.  The glucagon precursor contains at least 3 intervening sequences that divide the protein-coding portion into 4 regions corresponding to the signal peptide and part of the N-terminal peptide, the remainder of the N-terminal peptide and glucagon, glucagon-like peptide-1 (GLP1), and GLP2. The GLP 1 & 2 stimulates intestinal growth and upregulates villus height in the small intestine, concomitant with increased crupt cell proliferation and decreased enterocyte apoptosis. The two GLP’s are mainly produced in the A cells of the Islets of Langerhans in response to a drop in blood sugar concentration. GRF (Growth hormone-releasing factor) 44 aa peptide (chr 20q11.2) with a mass of 13kD is released by the hypothalamus and acts on the adenohypophyse to stimulate the secretion of Growth Hormone, GRF is mainly secreted by pancreatic islet cells, its antagonists inhibit the growth of various cancers in vivo. This effect is exerted in part by endocrinemechanisms through the inhibition of growth hormone (GH) releasefrom the pituitary.