title: Effects of salinity and prolactin on gene transcript levels of ion transporters, ion pumps and prolactin receptors in Mozambique tilapia intestine.
abstract: Euryhaline teleosts are faced with significant challenges during changes in salinity. Osmoregulatory responses to salinity changes are mediated through the neuroendocrine system which directs osmoregulatory tissues to modulate ion transport. Prolactin (PRL) plays a major role in freshwater (FW) osmoregulation by promoting ion uptake in osmoregulatory tissues, including intestine. We measured mRNA expression of ion pumps, Na(+)/K(+)-ATPase α3-subunit (NKAα3) and vacuolar type H(+)-ATPase A-subunit (V-ATPase A-subunit); ion transporters/channels, Na(+)/K(+)/2Cl(-) co-transporter (NKCC2) and cystic fibrosis transmembrane conductance regulator (CFTR); and the two PRL receptors, PRLR1 and PRLR2 in eleven intestinal segments of Mozambique tilapia (Oreochromis mossambicus) acclimated to FW or seawater (SW). Gene expression levels of NKAα3, V-ATPase A-subunit, and NKCC2 were generally lower in middle segments of the intestine, whereas CFTR mRNA was most highly expressed in anterior intestine of FW-fish. In both FW- and SW-acclimated fish, PRLR1 was most highly expressed in the terminal segment of the intestine, whereas PRLR2 was generally most highly expressed in anterior intestinal segments. While NKCC2, NKAα3 and PRLR2 mRNA expression was higher in the intestinal segments of SW-acclimated fish, CFTR mRNA expression was higher in FW-fish; PRLR1 and V-ATPase A-subunit mRNA expression was similar between FW- and SW-acclimated fish. Next, we characterized the effects of hypophysectomy (Hx) and PRL replacement on the expression of intestinal transcripts. Hypophysectomy reduced both NKCC2 and CFTR expression in particular intestinal segments; however, only NKCC2 expression was restored by PRL replacement. Together, these findings describe how both acclimation salinity and PRL impact transcript levels of effectors of ion transport in tilapia intestine.
authors.affiliation: Hawaii Institute of Marine Biology, University of Hawaii, Kaneohe, HI 96744, USA. Electronic address: seale@hawaii.edu.
authors.forename: Andre P
authors.initials: AP
authors.lastname: Seale
authors.affiliation: Hawaii Institute of Marine Biology, University of Hawaii, Kaneohe, HI 96744, USA; Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI 96822, USA.
authors.forename: Jacob J
authors.initials: JJ
authors.lastname: Stagg
authors.affiliation: Hawaii Institute of Marine Biology, University of Hawaii, Kaneohe, HI 96744, USA.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Yamaguchi
authors.affiliation: Department of Biology & Center for Neuroendocrine Studies, University of Massachusetts, Amherst, MA 01003, USA.
authors.forename: Jason P
authors.initials: JP
authors.lastname: Breves
authors.affiliation: Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, University of Tokyo, Bunkyo, Tokyo 113-8657, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Soma
authors.affiliation: Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, University of Tokyo, Bunkyo, Tokyo 113-8657, Japan.
authors.forename: Soichi
authors.initials: S
authors.lastname: Watanabe
authors.affiliation: Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, University of Tokyo, Bunkyo, Tokyo 113-8657, Japan.
authors.forename: Toyoji
authors.initials: T
authors.lastname: Kaneko
authors.affiliation: Department of Poultry and Aquaculture, The Volcani Center, Agricultural Research Organization, Bet Dagan 50250, Israel.
authors.forename: Avner
authors.initials: A
authors.lastname: Cnaani
authors.affiliation: Department of Poultry and Aquaculture, The Volcani Center, Agricultural Research Organization, Bet Dagan 50250, Israel.
authors.forename: Sheenan
authors.initials: S
authors.lastname: Harpaz
authors.affiliation: Hawaii Institute of Marine Biology, University of Hawaii, Kaneohe, HI 96744, USA; University of Hawaii Sea Grant College Program, University of Hawaii at Manoa, Honolulu, HI 96822, USA.
authors.forename: Darren T
authors.initials: DT
authors.lastname: Lerner
authors.affiliation: Hawaii Institute of Marine Biology, University of Hawaii, Kaneohe, HI 96744, USA.
authors.forename: E Gordon
authors.initials: EG
authors.lastname: Grau
mesh_terms: D000064:Acclimatization / Q000502:physiology; D000818:Animals; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics / Q000378:metabolism; D005618:Fresh Water; D005786:Gene Expression Regulation / Q000187:drug effects*; D007413:Intestinal Mucosa / Q000378:metabolism*; D007422:Intestines / Q000187:drug effects; D017136:Ion Transport / Q000502:physiology*; D011388:Prolactin / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D011981:Receptors, Prolactin / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D054712:Salinity; D012623:Seawater; D000254:Sodium-Potassium-Exchanging ATPase / Q000235:genetics / Q000378:metabolism; D064466:Solute Carrier Family 12, Member 1 / Q000235:genetics / Q000378:metabolism; D017210:Tilapia / Q000254:growth & development / Q000378:metabolism*; D025262:Vacuolar Proton-Translocating ATPases / Q000235:genetics / Q000378:metabolism; D014882:Water-Electrolyte Balance / Q000235:genetics
chemical_list: D012333:RNA, Messenger; D011981:Receptors, Prolactin; D064466:Solute Carrier Family 12, Member 1; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D011388:Prolactin; D025262:Vacuolar Proton-Translocating ATPases; D000254:Sodium-Potassium-Exchanging ATPase
keywords: Intestine; Ion transporters; Osmoregulation; Prolactin; Salinity; Tilapia