INVESTIGADORES
SOMOZA Gustavo Manuel
congresos y reuniones científicas
Título:
Secretoneurin- a secretogranin-II derived peptide with multiple neuroendocrine and paracrine actions.
Autor/es:
TRUDEAU, VANCE; WONG, ALEXANDER; ZHAO, E.; KO, W.; BASAK, A.; LOPEZ, GABRIELA CARINA; SCHARRIG, MARIA EMILIA; CANOSA; LUIS FABIAN; SOMOZA, GUSTAVO M.; CHANG, JOHN P.
Lugar:
Calgary, Canada
Reunión:
Congreso; 6th International Symposium on Fish Endocrinology.; 2008
Resumen:
Secretoneurin (SN) is a 33-34 amino acid neuropeptide derived from selective processing of the secretogranin-II (SgII) precursor protein, a member of the chromogranin family. Using a combination of reverse phase-HPLC and mass spectrometry analysis, we isolated for the first time a 34 amino acid free SN peptide from the goldfish (GF) brain. NMR analysis using grass carp (GC) SN indicate that SN is a helical peptide. SN has important roles to regulate anterior pituitary hormone release.  In GF, SN stimulates luteinizing hormone (LH) release in vivo and in vitro. Immunocytochemical studies on SN reveals a limited localization to prolactin cells in the GF rostral pars distalis. In GC, SN stimulates PRL gene expression in vitro. Immunocytochemical studies on SN reveals a limited localization to growth hormone (GH) cells in the GC pars distalis.  It is striking that SN has such a limited and differential distribution in these 2 cyprinids. However, this distribution reflects the specific processing of SgII in lactotrophs and somatotrophs, which share a common embryological origin. These comparative studies suggest that within the pituitary complex SN may be a new paracrine factor signaling between lactotrophs, somatotrophs and gonadotrophs. We also found that magnocellular isotocin neurons of the goldfish preoptic region are highly immunoreactive for SN. These neurons send abundant projections that pass through the pituitary stalk and innervate the neurointermediate lobe, and to a lesser extend the anterior lobe. We suggest that SN-IR products from both neural and endocrine origins may have a role in regulating pituitary function. Supported by NSERC (Canada), RGC Grant (Hong Kong), CONICET (Argentina).