title: Prolactin 177, prolactin 188, and extracellular osmolality independently regulate the gene expression of ion transport effectors in gill of Mozambique tilapia.
abstract: This study characterized the local effects of extracellular osmolality and prolactin (PRL) on branchial ionoregulatory function of a euryhaline teleost, Mozambique tilapia (Oreochromis mossambicus). First, gill filaments were dissected from freshwater (FW)-acclimated tilapia and incubated in four different osmolalities, 280, 330, 380, and 450 mosmol/kg H2O. The mRNA expression of Na(+)/K(+)-ATPase α1a (NKA α1a) and Na(+)/Cl(-) cotransporter (NCC) showed higher expression with decreasing media osmolalities, while Na(+)/K(+)/2Cl(-) cotransporter 1a (NKCC1a) and PRL receptor 2 (PRLR2) mRNA levels were upregulated by increases in media osmolality. We then incubated gill filaments in media containing ovine PRL (oPRL) and native tilapia PRLs (tPRL177 and tPRL188). oPRL and the two native tPRLs showed concentration-dependent effects on NCC, NKAα1a, and PRLR1 expression; Na(+)/H(+) exchanger 3 (NHE3) expression was increased by 24 h of incubation with tPRLs. Immunohistochemical observation showed that oPRL and both tPRLs maintained a high density of NCC- and NKA-immunoreactive ionocytes in cultured filaments. Furthermore, we found that tPRL177 and tPRL188 differentially induce expression of these ion transporters, according to incubation time. Together, these results provide evidence that ionocytes of Mozambique tilapia may function as osmoreceptors, as well as directly respond to PRL to modulate branchial ionoregulatory functions.
authors.affiliation: Hawaii Institute of Marine Biology, University of Hawaii, Kaneohe, Hawaii; Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo, Japan; and inokuchi@aori.u-tokyo.ac.jp.
authors.forename: Mayu
authors.initials: M
authors.lastname: Inokuchi
authors.affiliation: Department of Biology, Skidmore College, Saratoga Springs, New York;
authors.forename: Jason P
authors.initials: JP
authors.lastname: Breves
authors.affiliation: School of Marine Biosciences, Kitasato University, Sagamihara, Kanagawa, Japan;
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Moriyama
authors.affiliation: Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo, Japan; and.
authors.forename: Soichi
authors.initials: S
authors.lastname: Watanabe
authors.affiliation: Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo, Japan; and.
authors.forename: Toyoji
authors.initials: T
authors.lastname: Kaneko
authors.affiliation: Hawaii Institute of Marine Biology, University of Hawaii, Kaneohe, Hawaii; University of Hawaii Sea Grant College Program, University of Hawaii at Manoa, Honolulu, Hawaii.
authors.forename: Darren T
authors.initials: DT
authors.lastname: Lerner
authors.affiliation: Hawaii Institute of Marine Biology, University of Hawaii, Kaneohe, Hawaii; University of Hawaii Sea Grant College Program, University of Hawaii at Manoa, Honolulu, Hawaii.
authors.forename: E Gordon
authors.initials: EG
authors.lastname: Grau
authors.affiliation: Hawaii Institute of Marine Biology, University of Hawaii, Kaneohe, Hawaii;
authors.forename: Andre P
authors.initials: AP
authors.lastname: Seale
mesh_terms: D000818:Animals; D005109:Extracellular Matrix; D005786:Gene Expression Regulation / Q000502:physiology; D005880:Gills; D017136:Ion Transport / Q000502:physiology*; D008297:Male; D009994:Osmolar Concentration; D011388:Prolactin / Q000494:pharmacology*; D011981:Receptors, Prolactin / Q000235:genetics / Q000378:metabolism; D049992:Sodium Chloride Symporters / Q000235:genetics / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D017210:Tilapia / Q000502:physiology*; D015854:Up-Regulation
chemical_list: D011981:Receptors, Prolactin; D049992:Sodium Chloride Symporters; D011388:Prolactin; D000254:Sodium-Potassium-Exchanging ATPase
keywords: extracellular osmolality; ionocytes; prolactin; tilapia