title: The importance of the olfactory rosettes in maintaining pituitary prolactin and prolactin-releasing peptide levels during hyposmotic acclimation in silver sea bream (Sparus sarba).
abstract: A potential role of the olfactory rosettes in maintaining prolactin (PRL) and prolactin-releasing peptide (PrRP) levels was examined in the euryhaline silver sea bream (Sparus sarba). The olfactory rosettes were surgically removed in silver sea bream adapted to hypo- (6 ppt) and hyper-osmotic (33 ppt) salinities and the mRNA expression of the two previously identified freshwater-adapting factors, prolactin (PRL) and prolactin-releasing peptide (PrRP), in silver sea bream was measured. The elevation of pituitary PRL and PrRP mRNA expression levels as seen in 6 ppt-adapted fish was abolished by surgical removal of the olfactory rosettes. The PRL and PrRP expression levels in fish adapted to 6 ppt were significantly lowered following olfactory rosette removal. On the other hand, hypothalamic PrRP mRNA expression in 6 ppt-adapted fish did not change. Specific signals for Na(+)-K(+)-ATPase but not CFTR mRNA expression were detected in the surface layers of olfactory epithelial cells by in situ hybridization. The mRNA abundance of CFTR and Na(+)-K(+)-ATPase α and β subunits remained unchanged in the olfactory rosette of silver sea bream adapted to 0, 6, 12, 33 and 50 ppt for 4 weeks and in fish abruptly transferred from 33 ppt to 6 ppt. Data obtained from the olfactory rosette removal experiments suggest a possible role of the olfactory system for maintaining PRL and PrRP expression during hyposmotic acclimation in sea bream.
authors.affiliation: School of Life Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China.
authors.forename: Anna K Y
authors.initials: AK
authors.lastname: Kwong
authors.forename: Norman Y S
authors.initials: NY
authors.lastname: Woo
mesh_terms: D000064:Acclimatization; D000818:Animals; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics / Q000378:metabolism; D029941:Fish Proteins / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation; D009833:Olfactory Pathways / Q000378:metabolism*; D010473:Perciformes / Q000235:genetics / Q000378:metabolism*; D010902:Pituitary Gland / Q000378:metabolism*; D011388:Prolactin / Q000235:genetics / Q000378:metabolism*; D056690:Prolactin-Releasing Hormone / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D054712:Salinity; D015398:Signal Transduction; D000254:Sodium-Potassium-Exchanging ATPase / Q000235:genetics / Q000378:metabolism; D013997:Time Factors; D014882:Water-Electrolyte Balance
chemical_list: D029941:Fish Proteins; D056690:Prolactin-Releasing Hormone; D012333:RNA, Messenger; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D011388:Prolactin; D000254:Sodium-Potassium-Exchanging ATPase