title: Neuropeptide VF precursor
text: # Neuropeptide VF precursor
  
  Neuropeptide VF precursor, also known as pro-FMRFamide-related neuropeptide VF or RFamide-related peptide precursor, is a propeptide that in mammals is encoded by the NPVF (or RPFP) gene. The NPVF gene, and thus the propeptide, are expressed in neurons in the mediobasal hypothalamus. The propeptide is cleaved to form three other peptides, which are:
  
  * Neuropeptide SF (NPSF) (RFRP-1) – agonist of the $NPFF_1$ and $NPFF_2$ receptors $(EC_{50}$ = 29 nM and 0.0011 nM, respectively)
  * RFRP-2 – does not bind to either of the NPFF receptors; no known biological activity
  * Neuropeptide VF (NPVF) (RFRP-3) – agonist of the $NPFF_1$ receptor $(IC_{50}$ = 0.7 nM)
  
  NPSF and NPVF, originally referred to as the RFamide-related peptides RFRP-1 and RFRP-3, respectively, are the mammalian homologs of the avian neuropeptide gonadotropin-inhibitory hormone (GnIH). The mammalian NPVF and avian GnIH genes, along with their aforementioned peptide products, were discovered concurrently in 2000. Similarly to the avian GnIH neuropeptide, NPSF and NPVF have been found to potently inhibit gonadotropin secretion. Moreover, a potent and selective antagonist of the NPFF receptors, RF9, has been reported to possess "very strong" gonadotropin-releasing effects in vivo in male and female mice.
  
  