Plasma Concentrations of Arginine Vasotocin and Urotensin II Are Reduced Following Transfer of the Euryhaline Flounder (Platichthys flesus) from Seawater to Fresh Water

2002 ◽  
Vol 125 (1) ◽  
pp. 113-120 ◽  
Author(s):  
H Bond ◽  
M.J Winter ◽  
J.M Warne ◽  
C.R McCrohan ◽  
R.J Balment
1996 ◽  
Vol 199 (11) ◽  
pp. 2467-2475 ◽  
Author(s):  
M Vijayan ◽  
J Morgan ◽  
T Sakamoto ◽  
E Grau ◽  
G Iwama

We tested the hypothesis that nutritional state affects seawater acclimation by transferring either fed or food-deprived (2 weeks) male tilapia (Oreochromis mossambicus) from fresh water to full-strength sea water. Food-deprivation resulted in a significant increase in plasma concentrations of Na+, Cl-, cortisol, glucose, total amino acid, glutamate, serine and alanine, and in hepatic pyruvate kinase (PK) and lactate dehydrogenase (LDH) activities, whereas the prolactin-188 to prolactin-177 ratio (tPRL188:tPRL177) and plasma prolactin-188 (tPRL188), lactate, arginine and hepatic glycogen content and hepatic alanine aminotransferase (AlaAT) and 3-hydroxyacyl-Coenzyme A dehydrogenase (HOAD) activities were lower than in the fed group. Seawater transfer significantly increased the tPRL188:tPRL177 ratio and plasma concentrations of Na+, Cl-, K+, growth hormone (GH), glucose, aspartate, tyrosine, alanine, methionine, phenylalanine, leucine, isoleucine and valine levels as well as gill Na+/K+-ATPase activity and hepatic PK and LDH activities, whereas plasma tPRL177, tPRL188, glycine and lysine concentrations were significantly lower than in fish retained in fresh water. There was a significant interaction between nutritional state and salinity that affected the tPRL188:tPRL177 ratio and plasma concentrations of Cl-, GH, glucose, aspartate, tyrosine, serine, alanine, glycine, arginine and hepatic PK, LDH, AlaAT, aspartate aminotransferase, glutamate dehydrogenase and HOAD activities. These results, taken together, indicate that food-deprived fish did not regulate their plasma Cl- levels, despite an enhancement of plasma hormonal and metabolic responses in sea water. Our study also suggests the possibility that plasma prolactin and essential amino acids may be playing an important role in the seawater acclimation process in tilapia.


1974 ◽  
Vol 63 (2) ◽  
pp. 377-387 ◽  
Author(s):  
JACQUELINE PORTHÉ-NIBELLE ◽  
BRAHIM LAHLOU

SUMMARY Plasma cortisol concentrations, measured by competitive protein-binding, were examined in intact and hypophysectomized goldfish (Carassius auratus L.) adapted to fresh water or to 210 mm-sodium chloride solutions. The mean plasma cortisol concentration of freshwater-adapted fish (6·6 ± 1·8 (s.e.m.) μg/100 ml plasma) increased after stress and intraperitoneal injections of mammalian corticotrophin. Hypophysectomy resulted in a reduction in plasma cortisol concentration to about 2 μg/100 ml plasma. Transfer of fish to sodium chloride solutions caused rapid, but transitory increases in the plasma cortisol concentrations in intact, but not in hypophysectomized fish. After 3 days in the sodium chloride solution the cortisol levels were similar to those of control fish kept in fresh water. The plasma concentrations of this corticosteroid in goldfish appear to be unrelated to external salinity, although a 'mineralocorticoid' action of the hormone cannot be excluded.


Author(s):  
Gilmer Vanegas ◽  
Frédéric Lancien ◽  
Jérôme Leprince ◽  
Hubert Vaudry ◽  
Jean-Claude Le Mével

1985 ◽  
Vol 105 (3) ◽  
pp. 371-377 ◽  
Author(s):  
E. J. Nouwen ◽  
E. R. Kühn

ABSTRACT Adult male frogs (Rana ridibunda) were subjected to several volumetric and osmometric stimuli and the influence on circulating concentrations of arginine vasotocin (AVT) and mesotocin was studied by the use of highly specific radioimmunoassays. During progressive blood withdrawal (haemorrhage group) urine flow decreased to zero, whereas no change occurred in the plasma and urine osmolality. Control levels of 34·3±7·3 pmol AVT/1 gradually increased up to 638·3±179·1 pmol/l (P<0·001) after a blood loss of up to 50–60% of the blood volume. Plasma mesotocin concentrations also increased from 42·4±9·2 to 70·8±12·0 pmol/l (n = 7). Hypervolaemia, produced by the repeated intravenous injection of isotonic Ringer solution, increased the urine flow and osmolality compared to controls but had no influence on the plasma levels of AVT and mesotocin. Hypernatraemia without volume change profoundly increased the urine osmolality but the urine flow was not affected; the plasma concentrations of AVT and mesotocin remained at the control level. Finally, during a 1-h immobilization stress a pronounced antidiuresis occurred in the presence of a constant plasma and urine osmolality and control plasma levels of AVT and mesotocin. It is concluded that the release of AVT and, to a smaller extent, of mesotocin is under volumetric control. J. Endocr. (1985) 105, 371–377


1968 ◽  
Vol 49 (2) ◽  
pp. 325-339 ◽  
Author(s):  
G. L. FLETCHER ◽  
W. N. HOLMES

1. Intake of food, water and electrolyte by ducks maintained on fresh water and on hypertonic saline were measured over periods up to several months. 2. Transfer to saline approximately equivalent to 60% sea water was followed during the first 24 hr. by a sharp rise and fall in the plasma concentrations of sodium and chloride, which thereafter remained similar to the concentrations found in the freshwater-maintained birds. 3. Transfer to saline equivalent to 100% sea water resulted in a rise in these concentrations during the first 10 hr., which continued for a period up to 14 days, after which the birds either died or became unhealthy. 4. Upon transfer to saline drinking water (284 mM/l. Na+, 6.0 mM/l. K+) there was a gradual loss of body weight accompanied by a reduction in the food and water intake. Body weights tended to become stable after about 3 weeks, but some individuals continued to lose weight while others regained what they had lost. 5. When the concentration of sodium chloride in the drinking water exceeded 143 mM/l. the amount of sodium chloride ingested remained constant. Thus there was progressive decline in the volume of water drunk as the concentration increased. It would appear therefore that the saline-adapted duck possessed some mechanism whereby the daily intake of sodium chloride was regulated. 6. The cloacal output from saline-adapted ducks over a 24 hr. period showed that only 10% of the ingested sodium was excreted via this pathway as compared with over 70% of the ingested potassium. Most of the sodium appeared to be excreted via the nasal glands. 7. The possible interactions between the renal and extra-renal excretory pathways in the maintenance of homeostasis during adaptation to diets including hypertonic saline or seawater are discussed.


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