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 respons e (within a few hours). It encodes a 617-amino acid polypeptide (VGF p rotein) bearing no significant homology with known sequences and restr icted to certain peptide/amine-producing endocrine cells, and neurons (for example, adenohypophysial and adrenal medullary cells, or hypotha lamic neuroendocrine neurons). VGF is stored and transported in secret ory granules and processed to intermediate-small molecular weight prod ucts, 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 aff ecting 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.