A peptide called Neuropeptide Y has been known for some time to be present in brain and peripheral nerves of vertebrates, including in nerve fibers innervating the pancreas. It has been reported to have a number of actions, including effects on insulin release from the pancreas (islets of Langerhans). An analog of Neuropeptide Y, known as "aPY", has been characterized and was found to be synthesized as a precursor, pro-aPY, in one cell type of the anglerfish islets of Langerhans. (The anglerfish islets are an ideal experimental system for these studies because they are anatomically distinct structures in contrast to other vertebrates where the islet tissue is mingled with tissue of the exocrine pancreas.) A distinct form of Neuropeptide Y-like peptide has been identified in peripheral nerves present in the anglerfish islets. The objectives of the proposed research are: 1. To determine whether aPY is amidated (Amidation is necessary for maintainance of biological activity of many peptide mediators.) and, if so, to determine the characteristics of the enzyme responsible. 2. To determine the primary structure of the Neuropeptide Y-like peptide found in the islet neuronal tissue. 3. To determine the neurotransmitter in the neuronal processes that contain the neuronal form of Neuropeptide Y. 4. To study the effects of Neuropeptide Y, aPY, and the neuronal Neuropeptide Y-like peptides on islet hormone release. The results will provide the first information about the biologically active, distinct forms of Neuropeptide Y-like peptides from islet cells and from peripheral nerve fibers present in the islets, about the neurotransmitters which may be released coordinately with the peptides , and the roles of cellular and neuronal forms of NPY-like peptides in regulating insulin release from the islets.
