Influence of cortisol, growth hormone, insulin-like growth factor I and 3,3′,5-triiodo-l-thyronine on hypoosmoregulatory ability in the euryhaline teleost Fundulus heteroclitus     

J.M. Mancera  S.D. McCormick 《Fish physiology and biochemistry》1999,21(1):25-33

The capacity of cortisol, ovine growth hormone (oGH), recombinant bovine insulin-like growth factor I (rbIGF-I) and 3,3,5-triiodo-l-thyronine (T₃) to increase hypoosmoregulatory capacity in the euryhaline teleost Fundulus heteroclitus was examined. Fish acclimated to brackish water (BW, 10 ppt salinity) were injected with a single dose of hormone suspended in oil and transferred to seawater (SW, 35 ppt salinity) 10 days post-injection. Fish were sampled 24 h after transfer and plasma osmolality and gill Na⁺, K⁺-ATPase activity were examined. Transfer from BW to SW induced significantly increased plasma osmolality but not gill Na⁺, K⁺-ATPase activity. Cortisol (50 g g^–1 body weight) improved the ability to maintain plasma osmolality and to increase gill Na⁺, K⁺-ATPase activity. oGH (5 g g^–1 body weight) also increased hypoosmoregulatory ability and gill Na⁺, K⁺-ATPase activity. A cooperation between oGH and cortisol was observed in increasing hypoosmoregulatory ability but not in increasing gill Na⁺, K⁺-ATPase activity. rbIGF-I (0.5 g g^–1 body weight) alone was without effect in increasing salinity tolerance or gill Na⁺, K⁺-ATPase activity. rbIGF-I and oGH showed a positive interaction in increasing salinity tolerance, but not gill Na⁺, K⁺-ATPase activity. Treatment with T₃ (5 g g^–1 body weight) alone did not increase salinity tolerance or gill Na⁺, K⁺-ATPase activity, and there was no consistent significant interaction between cortisol and T₃ or between GH and T₃. The results confirm the classical role of cortisol as a seawater-adapting hormone and indicate an interaction between cortisol and the GH/IGF-I axis during seawater acclimation of Fundulus heteroclitus.  相似文献   

Quantification of presumptive Na+/H+ antiporters of the erythrocytes of trout and eel     

Scott D. Reid  Steve F. Perry 《Fish physiology and biochemistry》1994,12(6):455-463

The presumptive Na⁺/H⁺ exchange sites of trout and eel erythrocytes were quantified using amiloride-displaceable 5-(N-methyl-N-[³H]isobutyl)-amiloride (³H-MIA) equilibrium binding to further evaluate the mechanisms of i) hypoxia-mediated modifications in the trout erythrocyte -adrenergic signal transduction system and ii) the marked differences in the catecholamine responsiveness of this system between the trout and eel. MIA was a more potent inhibitor of both trout apparent erythrocyte proton extrusion (IC₅₀ = 20.1 ± 1.1 mol l^–1, N = 6) activity (as evaluated by measuring plasma pH changes after addition of catecholamine in vitro) and specific ³H-MIA binding (IC₅₀ = 257 ± 8.2 nmol l^–1, N = 3) than amiloride, which possessed a proton extrusion IC₅₀ of 26.1 ± 1.6 mol l^–1 (N = 6) and a binding IC₅₀ of 891 ± 113 nmol l^–1 (N = 3). The specific Na⁺ channel blocker phenamil was without effect on adrenergic proton extrusion activity or specific ³H-MIA binding. Trout erythrocytes suspended in Na⁺-free saline and maintained under normoxic conditions possessed 37,675 ± 6,678 (N = 6) amiloride-displaceable ³H-MIA binding sites per cell (B_max, presumptive Na⁺/H⁺ antiporters) with an apparent dissociation constant (K_D) of 244 ± 29 nmol l^–1 (N = 6). Acute hypoxia (PO₂ = 1.2 kPa; 30 min) did not affect the K_D, yet resulted in a 65% increase in the number of presumptive Na⁺/H⁺ antiporters. Normoxic eel erythrocytes, similarly suspended in Na⁺-free saline, possessed only 17,133 ± 3,716 presumptive Na⁺/H⁺ antiporters (N = 6), 45% of that of trout erythrocytes, with a similar K_D (246 ± 41 nmol l^–1, N = 6). These findings suggest that inter- and intra-specific differences in the responsiveness of the teleost erythrocyte -adrenergic signal transduction system can be explained, in part, by differences in the numbers of Na⁺/H⁺ exchange sites.  相似文献   

Ionoregulatory and respiratory responses of brown trout,Salmo trutta,exposed to lethal and sublethal aluminium in acidic soft waters     

Colin P. Waring  J. Anne Brown 《Fish physiology and biochemistry》1995,14(1):81-91

Soft water acclimated (Ca²⁺ 0.02 mM; Na⁺ 0.03 mM; K⁺ 0.01 mM; pH 7.0), cannulated brown trout (Salmo trutta) were exposed to various pH and aluminium (Al) regimes (pH 7.0, pH 5.0, pH 5.0 plus Al: 50, 25, and 12.5 g l^–1) for up to 5 days in order to determine (i) the sublethal concentration of Al at pH 5.0 for this species (ii) their ionoregulatory and respiratory status. No mortality or physiological disturbances were evident at pH 7.0 or pH 5.0. All trout died within 48 h at pH 5.0 in the presence of Al at 50 g l^–1 and 67% died over the 5 day period at pH 5.0 in the presence of Al at 25 g l^–1. Fish at these lethal Al concentrations showed significant decreases in arterial blood oxygen content (C_aO₂) but no changes in plasma osmolarity or the concentrations of plasma Na⁺, K⁺ and Cl^–. Physiological disturbance was more marked at the 50 g l^–1 Al concentration. The surviving fish at 25 g l^–1 showed few signs of physiological recovery while continually exposed to this regime. No fish died during the exposure to water of pH 5.0 containing 12.5 g l^–1 Al, but physiological disturbance was still apparent. These sublethally-stressed trout showed a transient decline in the plasma concentrations of Na⁺ and Cl^–1. Although C_aO₂ decreased, recovery was evident. The data suggest that in the brown trout, environmental Al concentration is as important as pH and calcium concentration in determining the physiological status of the fish.  相似文献   

Response of rainbow trout gill (Na++K+)-ATPase and chloride cells to T3 and NaCl administration     

Fabiana Trombetti  Vittoria Ventrella  Alessandra Pagliarani  Rodolfo Ballestrazzi  Marco Galeotti  Gianni Trigari  Maurizio Pirini  Anna Rosa Borgatti 《Fish physiology and biochemistry》1996,15(3):265-274

With the aim of comparing the effects of oral T₃ and NaCl administration on trout hypoosmoregulatory mechanisms, three groups of rainbow trout (Oncorhynchus mykiss Walbaum) held in freshwater (FW) were fed a basal diet (C), the same diet containing 8.83 ppm of 3,5,3-triiodo-L-thyronine (T₃) (T) or 10% (w/w) NaCl (N) respectively for 30 d. They were then transferred to brackish water (BW) for 22 d and fed on diet C. Gill (Na⁺+K⁺)-ATPase activity and its dependence on ATP, Na⁺ and pH, number of gill chloride cells (CC), serum T₃ level as well as fish growth, condition factor (K) and mortality were evaluated. During the FW phase, as compared to C trout, T trout showed a two fold higher serum T₃ level, had unchanged gill (Na⁺+K⁺)-ATPase activity and increased CC number, whereas N trout showed higher gill (Na⁺+K⁺)-ATPase activity and CC number. At the end of the experiment the enzyme activity was in the order T>N>C groups and all groups showed similar CC number. Both treatments changed the enzyme activation kinetics by ATP and Na⁺. A transient increase in K value occurred in N group during the period of salt administration. In BW, T and N groups had higher and lower survival than C group respectively. Other parameters were unaffected by the treatments. This trial suggests that T₃ administration promotes the development of hypoosmoregulatory mechanisms of trout but it leaves the (Na⁺+K⁺)-ATPase activity unaltered till the transfer to a hyperosmotic environment.  相似文献   

Cortisol-induced changes in oxygen consumption and ionic regulation in coastal cutthroat trout (Oncorhynchus clarki clarki) parr   总被引：2，自引：0，他引：2  

John D. Morgan  George K. Iwama 《Fish physiology and biochemistry》1996,15(5):385-394

The influence of cortisol on oxygen consumption and osmoregulatory variables was examined in coastal cutthroat trout (Oncorhynchus clarki clarki) parr kept in fresh water (FW) and transferred to seawater (SW). Intraperitoneal implants containing cortisol (50 g g^–1) in vegetable oil resulted in elevated plasma cortisol titres similar to those observed in fish following a 24h SW exposure. Cortisol treatment significantly increased the oxygen consumption and plasma glucose levels of trout in FW, consistent with the glucocorticoid role of cortisol. Cortisol treatment did not cause any changes in plasma ion concentrations or gill Na⁺,K⁺-ATPase activity in FW after 10 days. Cortisol-implanted fish exposed to SW for 24h showed slightly improved ion regulatory ability compare to non-implanted controls. The results of this study suggest that during SW transfer in juvenile salmonids, increases in cortisol may act as both a mineralocorticoid and a glucocorticoid, depending on the developmental state of the fish (e.g., smolt versus parr). Furthermore, the relative energetic costs of osmoregulation and that of the stress associated SW transfer cannot be discerned using whole-animal oxygen consumption rates.  相似文献   

Enhanced hypoosmoregulatory response to growth hormone after cortisol treatment in immature rainbow trout,Salmo gairdneri     

Steffen S. Madsen 《Fish physiology and biochemistry》1990,8(4):271-279

The growth-independent effect of ovine growth hormone (oGH) and oGH + cortisol treatment on seawater (SW) adaptation in immature rainbow trout, Salmo gairdneri was investigated. Fish were injected every second day with saline, 2.0 μg oGH/g or 2.0 μg oGH + 8.0 μg cortisol/g for a maximum of 8 injections in freshwater (FW). Subgroups were transferred to 28‰ SW after 4 or 8 injections, and changes in plasma Na⁺ and Cl⁻, muscle water content and gill Na⁺/K⁺-ATPase activity were measured. In both of the hormone-treated groups retained in FW, gill Na⁺/K⁺-ATPase activity and interlamellar chloride cell density increased. The effects were most pronounced in the oGH + cortisol group after 2 weeks of treatment. After transfer to SW most of the control fish died due to the osmotic stress, whereas in the hormone-treated groups, mortality was low and there was a positive correlation between pretransfer gill Na⁺/K⁺-ATPase and the ability to maintain ionic-osmotic homeostasis after SW transfer. After two weeks of oGH + cortisol treatment, gill Na⁺/K⁺-ATPase activity was maximal. In contrast, after SW transfer, Na⁺/K⁺-ATPase activity increased further in the oGH-treated group. This group regulated ionic-osmotic parameters less effectively than the oGH + cortisol-treated group. The data indicate that GH and cortisol are important hormones in the regulation of hypoosmoregulatory mechanisms in S. gairdneri.  相似文献   

Osmoregulation in the mudskipper,Boleophthalmus boddaerti I. Responses of branchial cation activated and anion stimulated adenosine triphosphatases to changes in salinity     

Ip  Y. K.  Lee  C. G. L.  Low  W. P.  Lam  T. J. 《Fish physiology and biochemistry》1991,9(1):63-68

The mudskipperB. boddaerti, was able to survive in waters of intermediate salinities (4–27). Fish submerged in dechlorinated tap water suffered 60% mortality by the fifth day while 60% of those in 100% sea-water (sw) died after the third day of exposure. After being submerged in 50% or 80% sw for 7 days, the plasma osmolality, plasma Na⁺ and Cl^– concentrations and the branchial Na⁺ and K⁺ activated adenosine triphosphatase (Na⁺,K⁺-ATPase) activity were significantly higher than those of fish submerged in 10% sw for the same period. However, the activities of the branchial HCO₃ ^– and Cl^– stimulated adenosine triphosphatase (HCO₃ ^–,Cl^–-ATPase) and carbonic anhydrase of the latter fish were significantly greater than those of the former. Such correlation suggests that Na⁺,K⁺-ATPase is important for hyperosmotic adaptation in this fish while HCO₃ ^–-Cl^–-ATPase and carbonic anhydrase may be involved in hypoosmotic survival.  相似文献   

The effect of dietary sodium chloride on some osmoregulatory parameters of the teleost, Oreochromis niloticus, after transfer from freshwater to seawater   总被引：1，自引：0，他引：1  

A. Fontaínhas-Fernandes  F. Russell-Pinto  Emídio Gomes  Ma.A. Reis-Henriques  João Coimbra 《Fish physiology and biochemistry》2000,23(4):307-316

The aim of this work was to determine the effects of supplemental dietary sodium chloride on salt water acclimation of tilapia Oreochromis niloticus. Fish were fed a basal diet supplemented with NaCl (8%) during three weeks in fresh water (FW) and then transferred to salt water (SW) at 15 and 20. Changes in plasma osmolality, chloride ion concentration (Cl^–), plasma level of cortisol and gill Na⁺, K⁺-ATPase activity were measured at 6, 12, 24, 48, 72 and 168 h after transfer to 15SW, while the higher strength SW group (20) was only monitored up to 24 h. Morphological changes in the gill mitochondria-rich (MR) cells were examined in relation to environmental salinity. The changes associated with dietary NaCl were sporadic and of small magnitude. The plasma osmolality and Cl^– increased immediately after transfer up to 12–24 h, but fish fed dietary salt (S) showed lower values than the control group (C). The S group showed higher plasma levels of cortisol than the control, which maintained its initial levels during the experiment. Gill Na⁺, K⁺-ATPase activity of the S group began to increase in the first hours after transfer, reaching maximum at 12 h and returned to basal level at 24 h, while the control group maintained basal levels. The differences between gill Na⁺, K⁺-ATPase activity of S and C fish were significant (p < 0.05) at 12 h. Transmission electron microscopy (TEM) revealed that MR cells in SW show more mitochondria and a more developed tubular system arising from the basolateral membrane. The MR cells of both groups frequently formed a multicellular complex in SW, consisting of a main MR and one or more accessory cells. Such complexes are rarely observed in FW. Some MR cells of fish fed supplemented dietary salt displayed convex apical membrane in FW.  相似文献   

盐度胁迫对三疣梭子蟹鳃Na⁺/K⁺-ATPase酶活的影响   总被引：2，自引：2，他引：0  

江山  许强华 《水产学报》2011,35(10):1475-1480

通过钼蓝法测定三疣梭子蟹在3组实验盐度的胁迫过程中第2对和第6对鳃Na⁺/K⁺-ATPase酶活的变化,比较了3组实验盐度胁迫1 d时,鳃Na⁺/K⁺-ATPase的酶活大小。结果表明,在盐度胁迫初期,3组实验盐度下第2对和第6对鳃Na⁺/K⁺-ATPase的酶活下降;之后,各组实验盐度下第2对和第6对鳃Na⁺/K⁺-ATPase的酶活开始随胁迫时间增长而上升;最后,各组实验盐度下第2和第6对鳃Na⁺/K⁺-ATPase的酶活下降并趋于稳定。另外,胁迫1 d时,各组实验盐度下三疣梭子蟹前5对鳃Na⁺/K⁺-ATPase的酶活显著低于后3对鳃Na⁺/K⁺-ATPase的酶活。三疣梭子蟹对盐度变化的调节可分为被动应激期(酶活力下降)、主动调节期(酶活力逐渐上升)和适应期(酶活力稳定);三疣梭子蟹后3对鳃是离子转运、渗透压调节的主要部位。  相似文献   

Sodium dependent ion transporters in trout gills     

G. Flik  T. Kaneko  A.M. Greco  J. Li  J.C. Fenwick 《Fish physiology and biochemistry》1997,17(1-6):385-396

Biochemical procedures developed to isolate plasma membranes from the branchial epithelium of rainbow trout (Oncorhynchus mykiss) yield membrane fractions that are specifically enriched in the plasma membrane marker enzyme Na⁺/K⁺-ATPase. As the bulk of the branchial Na⁺/K⁺-ATPase is assumed to be confined to the mitochondria-rich chloride cells, such membrane preparations must contain the essence of the enzymatic machinery of the chloride cells. Basal Na⁺ activity in branchial (chloride) cells is around 10 millimolar and, accordingly, we find a K_m for Na⁺ of the Na⁺/K⁺-ATPase of 13 millimolar, indicating that the enzyme may be regulated by changes in cytosolic sodium. The Na⁺-gradient across the serosal plasma membrane created by this pump provides energy for 3Na⁺/Ca²⁺-exchange and bumetanide-sensitive Na⁺/K⁺/2Cl^--cotransport. Here we further postulate the presence of a Na⁺/Cl^--cotransporter, indicated by thiazide-sensitive, bumetanide-insensitive transport of Na⁺ and Cl^-; this cotransporter activity awaits the characterization of its kinetics. The Na⁺/Ca²⁺-exchanger has kinetic characteristics compatible with a regulatory role of cytosolic Na⁺ in the activity of this carrier. Both Na⁺/Ca²⁺-exchange and Ca²⁺-ATPase activity may contribute to transport of Ca²⁺, the former having lower affinity for calcium but a higher capacity than the latter carrier. The Na⁺/K⁺/2Cl^--cotransporter has kinetics that favor a regulatory role for plasma K⁺ in the activity of this carrier. Seawater adaptation leads to increased activity of cotransporter molecules in the plasma membrane fractions (the activity increases relative to that of the Na⁺/K⁺-ATPase) and this may reflect a function in Cl^--extrusion performed by the chloride cells in a seawater environment. A function for the cotransporter in the gills of freshwater fish may be the regulation of cell volume.  相似文献   

Osmoregulation in juvenile Chinese sturgeon (<Emphasis Type="Italic">Acipenser sinensis</Emphasis> Gray) during brackish water adaptation     

Xugang He  Ping Zhuang  Longzhen Zhang  Congxin Xie 《Fish physiology and biochemistry》2009,35(2):223-230

The osmoregulation capabilities of 7-month-old juvenile Chinese sturgeon (Acipenser sinensis Gray) (128.8 ± 15 g) transferred directly from fresh water (0‰, 46 mOsmol kg⁻¹) to brackish water (10‰, 273 mOsmol kg⁻¹) were studied over a 20-day period. Changes in serum osmolarity, chloride (Cl⁻), sodium (Na⁺), potassium (K⁺) and calcium (Ca²⁺) ion concentrations, as well as gill and spiral valve Na⁺,K⁺-ATPase activities were measured at 3, 12, 24, 72, 216 and 480 h after transfer to BW. The serum osmolarity and ion concentrations (Na⁺, Cl⁻ and Ca²⁺) increased immediately after the transference to BW, reaching maximum at 24 h and returned to a new steady state at 216 h, while the FW control group maintained basal levels which showed lower (P < 0.05) than the BW group. Gill Na⁺,K⁺-ATPase activity of BW group exhibited an abrupt decrease in the first 3 h after transfer, but began to increase at 3 h, reaching a peak value at 24 h, and returned to a new steady state at 216 h. The differences between gill Na⁺,K⁺-ATPase activity of BW and FW fish were significant (P < 0.05) after 12 h. In contrast, Na⁺,K⁺-ATPase activity of the spiral valve showed transient increase after transference from FW to BW, and then decreased rapidly at 3 h, reaching the lowest at 24 h after transference. At 216 h after exposure to BW, Na⁺,K⁺-ATPase activities of the spiral valve increased slowly to the levels of FW control. The results of our study indicate the existence of hyposmoregulatory adaptive mechanisms in 7-month-old juvenile Chinese sturgeon which enable this fish to acclimate itself successfully to brackish water.  相似文献   

Cortisol treatment improves the development of hypoosmoregulatory mechanisms in the euryhaline rainbow trout,Salmo gairdneri     

Steffen S. Madsen 《Fish physiology and biochemistry》1990,8(1):45-52

The effect of cortisol on osmoregulatory parameters was studied in rainbow trout, (Salmo gairdneri), kept in freshwater (FW) and/or transferred to seawater (SW). Repeated injections of 20 μg cortisol/g fish stimulated gill and gut Na⁺/K⁺-ATPase activity and reduced plasma Na⁺ and Cl⁻ levels after 2 weeks of treatment in FW-adapted fish. Cortisol doses of 0.05 and 1.0 μg/g were without effect. Repeated injections of 10 μg cortisol/g stimulated gill Na⁺/K⁺-ATPase activity and reduced plasma Na+ and Cl⁻ levels in fish in FW, and significantly improved ion regulation after their transfer to 28SW. Higher doses of cortisol (10 and 20 μg/g) induced hyperglycemia, whereas low doses (0.05 and 1.0 μg/g were without effect or induced hypoglycemia. Plasma glucose levels decreased in cortisol-treated fish transferred to SW, whereas transient hyperglycemia was seen in the control fish.  相似文献   

Lipid composition and microsomal ATPase activities in gills and kidneys of warm- and cold-acclimated sea bass (Dicentrarchus labrax L.)     

V. Ventrella  A. Pagliarani  M. Pirini  G. Trigari  F. Trombetti  A. R. Borgatti 《Fish physiology and biochemistry》1993,12(4):293-304

The response to cold of gill and kidney membrane lipid composition and microsomal (Na⁺+K⁺)-ATPase, Na⁺-ATPase and Mg²⁺-ATPase activities in reared sea bass (Dicentrarchus labrax L.) was investigated. Fish acclimation was carried out according to the seasonal cycle from August to March. No cold-promoted increase in fatty acid unsaturation was shown in gill and kidney polar lipids and in total lipids of mitochondria and microsomes. In both tissues the (Na⁺+K⁺)-ATPase exhibited positive compensation for cold acclimation whereas the Na⁺-ATPase displayed negative compensation. The Mg²⁺-ATPase showed no compensation in the gills and positive compensation in the kidneys. During cold acclimation the break in the Arrhenius plot of the (Na⁺+K⁺)-ATPase decreased, whereas breaks of both the Na⁺-ATPase and the Mg²⁺-ATPase activities remained unchanged. The results indicate that the sea bass does not adopt membrane unsaturation as a cold-facing strategy. The cold-promoted enhancement of (Na⁺+K⁺)-ATPase activity in osmoregulatory tissues may be advantageous to maintain efficient osmoregulation under thermodynamically unfavourable conditions.  相似文献   

Effects of 17β-estradiol and 4-nonylphenol on smoltification and vitellogenesis in Atlantic salmon (Salmo salar)     

S.S. Madsen  A.B. Mathiesen  B. Korsgaard 《Fish physiology and biochemistry》1997,17(1-6):303-312

The impact of 17-estradiol (E₂) and the putative estrogenic compound, 4-nonylphenol (4-NP), on smoltification and vitellogenesis in Atlantic salmon (Salmo salar) was investigated during a 30 day period starting late April. Three groups of fresh water (FW) fish (1 year old, mixed sexes, average weight 23 g) were injected once a week with 50 µg (0.18 µmol) 17-estradiol, 3 mg (13.6 µmol) 4-nonylphenol dissolved in peanut oil, or peanut oil alone as control. Every ten days, subgroups were challenged with 28 ppt seawater (SW) for 24h, and sampled together with subgroups of FW fish. Treatment effects were examined on vitellogenic and osmoregulatory parameters. E₂ and 4-NP treatment increased the total calcium and protein level in plasma and the hepatosomatic index of FW fish, both indicating an activated vitellogenesis in the liver. The presence of vitellogenin in the plasma of 4-NP- and E₂-treated groups was further indicated by the appearance of a high molecular weight vitellogenin band (550 kDa) in electropherograms produced by native gel electrophoresis. This band appeared in exactly the same position in both the E₂- and the 4-NP-treated groups but could not be detected in controls. During the 30 day treatment period, control fish approached the peak of smoltification, as indicated by a distinct silvery appearance, decreasing condition factor, increasing levels of gill Na⁺,K⁺-ATPase and improved hypoosmoregulatory performance in the SW-challenge test. Both E₂ and 4-NP treatments significantly inhibited the progress of smoltification, as judged by a significant reduction of gill Na⁺,K⁺-ATPase activity, relative -subunit Na⁺,K⁺-ATPase mRNA expression, gill chloride cell density and a poorer hypoosmoregulatory performance of treated fish. The impaired SW-tolerance of E₂- and 4-NP-treated fish was strongly correlated with a decreased gill Na⁺,K⁺-ATPase activity. Despite a difference in relative potency, the present study shows that 4-nonylphenol and 17-estradiol may have qualitatively similar inhibitory effects on smoltification and hypoosmoregulatory physiology of Atlantic salmon. Both 4-NP and E₂ activated the vitellogenic system, and the study supports the hypothesis that sexual maturation and smoltification are antagonistic, developmental phenomena in salmon. It is suggested that the presence of estrogenic compounds in the environment may negatively influence smoltification and migration in wild stocks of salmon.  相似文献   

Immunohistochemical study on changes in gill Na+/K+-ATPase α-subunit during smoltification in the wild masu salmon, Oncorhynchus masou     

K. Ura  S. Mizuno  T. Okubo  Y. Chida  N. Misaka  S. Adachi  K. Yamauchi 《Fish physiology and biochemistry》1997,17(1-6):397-403

Changes in immunoreactivity of Na⁺/K⁺-ATPase -subunit in gill sections of wild masu salmon (Oncorhynchus masou) during the parr-smolt transformation (smoltification) were compared with changes in gill Na⁺/K⁺-ATPase specific activity. Gill Na⁺/K⁺-ATPase specific activity increased from April and peaked in May. Immunohistochemical analysis, using an antiserum against a synthetic oligopeptide based on the conserved region of the Na⁺/K⁺-ATPase -subunit, revealed that immunoreactivity was confined to chloride cells in the surface layer of primary lamellae and the proximal end of secondary lamellae. The size and number of these cells increased gradually from February to May; however, the number of chloride cells of the secondary lamellae decreased in May. These data suggest that the synthesis of Na⁺/K⁺-ATPase and the proliferation of chloride cells occur prior to the elevation of enzyme activity. Moreover, it is likely the proliferation and hypertrophy of chloride cells on primary lamellae prepare smolts for entry into seawater and migration in the ocean.  相似文献   

Effects of Na/K and Mg/Ca ratios in saline groundwaters on Na-K-ATPase activity, survival and growth of Marsupenaeus japonicus postlarvae     

Lu-Qing Pan  Zhi-Hua Luan  Cai-Xia Jin 《Aquaculture (Amsterdam, Netherlands)》2006,261(4):1396-1402

The effects of the Na⁺/K⁺ and Mg²⁺/Ca²⁺ ratios in saline groundwaters on Na⁺-K⁺-ATPase activity, survival and growth of Marsupenaeus japonicus postlarvae were investigated. The results indicate that the Na⁺-K⁺-ATPase activity, survival rate and weight gain of postlarvae were significantly affected by the Na⁺/K⁺ and Mg²⁺/Ca²⁺ ratios (P < 0.05). The Na⁺-K⁺-ATPase activity of postlarvae, in every treatment, changed corresponding to Na⁺/K⁺ and Mg²⁺/Ca²⁺ ratios, and came to a stable level after 24 h. There was a negative relation between Na⁺-K⁺-ATPase activity and Na⁺/K⁺ ratio, while there was a positive relation between Na⁺-K⁺-ATPase activity and Mg²⁺/Ca²⁺ ratio. Compared with seawater (the Na⁺/K⁺ and Mg²⁺/Ca²⁺ ratios are 27.8 and 4.64 respectively), the Na⁺-K⁺-ATPase activity of the Na⁺/K⁺ ratio 30 treatment showed no significant difference, while the Mg²⁺/Ca²⁺ ratio 4.5 treatment showed distinct difference. The survival rates and weight gain of postlarvae increased markedly when the suitable amount of K⁺ and Ca²⁺ was added to test water, and arrived at their maximum in the Na⁺/K⁺ ratio 20-30 or Mg²⁺/Ca²⁺ ratio 4.5 treatment, having no significant difference compared with normal seawater. Therefore, considering the Na⁺/K⁺, Mg²⁺/Ca²⁺ ratios and the absolute concentration of Mg²⁺, Ca²⁺ in the experimental saline groundwaters applied to Marsupenaeus japonicus farming, it should be modulated to around 30, 4.5 and 1312 mg/l, 291 mg/l, respectively.  相似文献   

Influence of salinity on the energetics of gill and kidney of Atlantic salmon (Salmo salar)     

Stephen D. McCormick  Christopher D. Moyes  James S. Ballantyne 《Fish physiology and biochemistry》1989,6(4):243-254

The effect of seawater acclimation and adaptation to various salinities on the energetics of gill and kidney of Atlantic salmon (Salmo salar) was examined. Smolts and non-smolts previously reared in fresh water were exposed to a rapid increase in salinity to 30 ppt. Plasma osmolarity, [Na⁺], [Cl^–], [K⁺] and [Mg⁺⁺] increased in both groups but were significantly lower in smolts than non-smolts. Gill Na⁺, K⁺-ATPase specific activity, initially higher in smolts, increased in both groups after 18 days in seawater. Kidney Na⁺, K⁺-ATPase specific activity was not affected by salinity in either group. Gill and kidney citrate synthase specific activity was not affected by seawater exposure in smolts but decreased in non-smolts. In a second experiment, Atlantic salmon smolts reared in fresh water were acclimated to 0, 10 or 30 ppt seawater for 3 months at a temperature of 13–14°C. Gill Na⁺, K⁺-ATPase was positively correlated with salinity, displaying 2.5- and 5-fold higher specific activity at 10 and 30 ppt, respectively, than at 0 ppt. Kidney Na⁺, K⁺-ATPase specific activity was not significantly affected by environmental salinity. Citrate synthase and cytochrome c oxidase specific activities in gill were slightly (6–13%) lower at 10 ppt than at 0 and 30 ppt, whereas kidney activities were lowest at 30 ppt. Oxygen consumption of isolated gill filaments was significantly higher when incubated in isosmotic saline and at 30 ppt than at 0 ppt, but was not affected by the prior acclimation salinity. The results indicate that although high salinity induces increased gill Na⁺, K⁺-ATPase activity, it does not induce substantial increases in metabolic capacity of gill or kidney.  相似文献   

Cortisol stimulates intestinal fluid uptake in Atlantic salmon (Salmo salar) in the post-smolt stage     

Sean C. Cornell  David M. Portesi  Philip A. Veillette  Kristina Sundell  Jennifer L. Specker 《Fish physiology and biochemistry》1994,13(3):183-190

The fluid uptake rate of the posterior intestine of salmonids increases during the parr-smolt transformation. Intestinal fluid uptake in post-smolt Atlantic salmon was investigated after treatment with cortisol and growth hormone (GH), alone or together. Two replicate experiments were conducted in August 1991 and August 1992. Cortisol was emulsified in vegetable shortening and vegetable oil (1:1) and implanted into the peritoneal cavity. GH was administered as intraperitoneal injections in a saline vehicle on days 0 and 2. On days 5 and 6, plasma cortisol levels, gill Na⁺,K⁺-ATPase activity, andin vitro measurements of fluid transport rate (J_v) across the posterior intestine were measured. Implants of cortisol elevated the plasma cortisol levels within a physiological range, and resulted in elevated gill Na⁺,K⁺-ATPase activity, as expected. The fluid uptake rate across the posterior intestine was roughly doubled by cortisol treatment. GH treatment did not affect intestinal fluid transport, gill Na⁺,K⁺-ATPase activity, or plasma cortisol concentrations. The seawater-adapting increase in the rate of fluid uptake by the posterior intestine of smolting salmon is probably stimulated by elevated plasma cortisol concentrations.  相似文献   

Characterization of transport Na+-ATPases in gills of freshwater tilapia     

Dr. Paul Balm  Nico Goossen  Sjef van de Rijke  Sjoerd Wendelaar Bonga 《Fish physiology and biochemistry》1988,5(1):31-38

Branchial plasma membranes from the freshwater cichlid teleostOreochromis mossambicus (tilapia) contain two Na⁺-dependent ATPases: Na⁺/K⁺ ATPase, and an amiloride-sensitive ATPase which is postulated to operate as a Na⁺/H⁺ (–NH₄ ⁺) ATPase. It is suggested that both enzyme activities are located in the basolateral membrane system of the chloride cells. K⁺ has opposing effects on the two enzymes: it stimulates Na⁺/K⁺ ATPase and inhibits Na⁺/H⁺ (–NH₄ ⁺) ATPase activity. Na⁺/H⁺ ATPase appears more sensitive to NH₄ ⁺ at low concentrations than Na⁺/K⁺ ATPase and the stimulatory effect by NH₄ ⁺ ions on the first enzyme could be important in facilitating NH₄ ⁺ excretion by tilapia gills under physiological conditions.In vitro maximum stimulation by NH₄ ⁺ is similar for the two enzymes (200%). In contrast to Na⁺/K⁺ ATPase, Na⁺/H⁺ ATPase activity is inhibited by supra-physiological (>20 mM) concentrations of NH₄ ⁺.  相似文献   

Effects of ambient ion concentrations on gill ATPases in fresh water eel,Anguilla anguilla     

N. Mayer-Gostan  R. Naon 《Fish physiology and biochemistry》1992,10(1):75-89

Branchial activities of Na⁺,K⁺-ATPase (ouabain sensitive), Mg²⁺ ATPase (ouabain insensitive) and kinetic analysis of high and low affinity Ca²⁺ ATPase were measured inAnguilla anguilla that had been acclimated to demineralized water (DW, Ca < 10 M), freshwater (FW, Ca = 2 mM), and Low calcium freshwater (L-Ca, Ca = 0.9 mM). Na⁺,K⁺-ATPase activity decreased while ouabain insensitive activity increased when ambient Ca²⁺ decreased. Two kinetic forms of Ca²⁺ ATPase could be resolved in each environmental condition. The stimulation coefficients of both sites or enzymes were not affected by ambient Ca²⁺ concentrations. The maximal velocity of both the high and the low affinity Ca²⁺ ATPase was increased when external Ca²⁺ was decreased during acclimation. The low affinity Ca²⁺ ATPase and the Mg²⁺ stimulated enzyme could be a non specific enzyme accepting either Ca²⁺ or Mg²⁺. Results are compared with previous results in the literature and in relation to the branchial morphology and ionic exchanges in fish.  相似文献