Purification of a glucagon releasing factor from the rat hypothalamus

The purification of a peptide from the rat hypothalamus which is capable of stimulating the release of glucagon from the endocrine pancreas and therefore named glucagon releasing factor (GlRF), is described. Compositional analysis of the product obtained using well established techniques for peptide isolation revealed that GlRF appeared to consist of 30-31 amino acids. The significance of GlRF in the physiological regulation of glucagon secretion is yet to be determined but the existence of this very potent factor supports the concept of a hypothalamic-pancreatic neurohormonal link.