Role of obestatin on growth hormone secretion: An in vitro approach.
Obestatin, the ghrelin-associated peptide, showed to activate MAPK signaling with no effect on Akt nor cell proliferating activity in rat tumor somatotroph cells (growth cells, GC). A sequential analysis of the obestatin transmembrane signaling pathway indicated a route involving the consecutive activation of G(i), PI3k, novel PKCepsilon, and Src for ERK1/2 activation. Furthermore, obestatin treatment triggers growth hormone (GH) release in the first 30min, being more acute at 15min. At 1h, obestatin treated cells showed the same levels in GH secretion than controls. Added to this functionality, obestatin was secreted by GC cells. Based on the capacity to stimulate GH release from somatotroph cells, obestatin may act directly in the pituitary through an autocrine/paracrine mechanism.
Pazos
Yolanda
Y
Area de Endocrinología Molecular y Celular, Instituto de Investigación Sanitaria (IDIS), Complejo Hospitalario Universitario de Santiago (CHUS), Santiago de Compostela, Spain. yolanda.pazos@usc.es
Alvarez
Carlos J P
CJ
Camiña
Jesús P
JP
Al-Massadi
Omar
O
Seoane
Luísa M
LM
Casanueva
Felipe F
FF
D000818:Animals; D045744:Cell Line, Tumor; D004789:Enzyme Activation; D054439:Ghrelin / Q000494:pharmacology*; D013006:Growth Hormone / Q000378:metabolism*; D051379:Mice; D048052:Mitogen-Activated Protein Kinase 3 / Q000096:biosynthesis; D019869:Phosphatidylinositol 3-Kinases / Q000096:biosynthesis; D051744:Protein Kinase C-epsilon / Q000096:biosynthesis; D051381:Rats; D052683:Somatotrophs / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D019061:src-Family Kinases / Q000096:biosynthesis
D054439:Ghrelin; D013006:Growth Hormone; D019869:Phosphatidylinositol 3-Kinases; D019061:src-Family Kinases; D051744:Protein Kinase C-epsilon; D048052:Mitogen-Activated Protein Kinase 3