Secretoneurin: a conserved hormonal peptide with paracrine and neuroendocrine actions to regulate pituitary function.

VANCE L. TRUDEAU; ZHAO, E.; HONGXIA HU; GUSTAVO M. SOMOZA; CHRIS MARTYNIUK; AJOY BASAK

Buenos Aires

Congreso; 7th International Symposium on Fish Endocrinology.; 2012

Secretoneurin (SN) is 31-42 amino acid peptide derived from selective processingof secretogranin-II. Immunoreactivity for SN is found either in lactotrophs,somatotrophs or somatolactotrophs, depending on the species. In goldfish, SN isreleased from lactotrophs under GnRH stimulation to enhance LH release fromadjacent gonadotrophs by a paracrine mechanism. SN is found in magnocellularisotocin neurons and in other hypophysiotropic neurons, e.g., nucleus lateralistuberis. SN also stimulates LH release by a neuroendocrine mechanism. Microarrayanalysis of dispersed pituitary cells in vitro revealed other functions of SN; ~500transcripts were increased and ~200 transcripts were decreased after SN treatment.These included genes important for the notch pathway, glucose metabolism andthe guanylate cyclase pathway. Pathway enrichment and sub-network enrichmentanalysis revealed that SN affects the same network of genes that are affectedinterferon gamma (INFG) and brain-derived neurotrophic factor. That SN sharesexpression targets with the cytokine INFG strengthens the notion that SN is actingas a paracrine signaling molecule. We suggest that SN is part of a growing list ofvertebrate intrapituitary factors regulating cellular metabolism and hormonesynthesis.