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Abstract
Gonadotropin-inhibitory hormone (GnIH) is a hypothalamic RFamide-related peptide that inhibits gonadotropin release in birds. The orthologous RFamide gene sequence and function of GnIH in the pig is not known. A partial cDNA was isolated for the porcine Rfrp gene and the amino acid sequence identified to reveal that the porcine gene codes for the RFamide peptides; RFRP-1 and RFPR-3, and RFRP-2. Using immunohistochemistry, RFamide containing neurons within the porcine hypothalamus were most abundant in the supraoptic nucleus, lateral preoptic area, and the paraventricular nucleus. Peripheral administration of RFRP-3 to ovariectomized (OVX) prepubertal gilts reduced LH pulse amplitude and mean concentrations of LH after treatment. Central administration of RFRP-3 to OVX prepubertal gilts suppressed amplitude and frequency of LH pulses. These data suggest that RFRP-3can regulate pulsatile secretion of LH in the OVX prepubertal gilt.