vgf - A neurotrophin-inducible gene expressed in neuroendocrine tissues

vgf is an inducible gene, highly sensitive to nerve growth factor (NGF) and remarkably upregulated in the ''early-delayed'' phase of response (within a few hours). It encodes a 617-amino acid polypeptide (VGF protein) bearing no significant homology with known sequences and restricted to certain peptide/amine-producing endocrine cells, and neurons (for example, adenohypophysial and adrenal medullary cells, or hypothalamic neuroendocrine neurons). VGF is stored and transported in secretory granules and processed to intermediate-small molecular weight products, which are preferentially released. Striking changes in both VGF mRNA and immunolocalization are found in physiological conditions (for example, estrous cycle) and in experimental models of stimulation affecting hypothalamic and other neurons. Functional roles of VGF are to be sought in secretory granule formation and regulation, and/or in the production of potentially bioactive peptides.