scholarly journals Early changes in the plasma osmolality and ionic concentrations of rainbow trout and goldfish following direct transfer from fresh-water to sea water.

1977 ◽  
Vol 43 (11) ◽  
pp. 1253-1257 ◽  
Author(s):  
Mikio OGURI ◽  
Yôjiro OOSHIMA
Aquaculture ◽  
1998 ◽  
Vol 168 (1-4) ◽  
pp. 351-367 ◽  
Author(s):  
Arne M Arnesen ◽  
Helge K Johnsen ◽  
Atle Mortensen ◽  
Malcolm Jobling

1978 ◽  
Vol 56 (11) ◽  
pp. 2394-2401 ◽  
Author(s):  
K. J. Brewer ◽  
B. A. McKeown

Ergocryptine, an ergot alkaloid that suppresses prolactin (PRL) secretion and also affects growth hormone (GH) levels in mammals, was injected into juvenile rainbow trout, Salmo gairdneri, averaging 8 to 31 g. In fresh water the drug caused few fatalities but lowered plasma Na+, plasma Ca2+, muscle K+, muscle Mg2+, and haematocrit values. The simultaneous injection of low doses of PRL or GH did not significantly modify the results obtained with the drug alone except for an increase in muscle Mg2+ levels. This suggests a possible peripheral action of the drug.Ergocryptine caused the death of S. gairdneri in dilute sea water, while in certain circumstances PRL and GH prevented mortalities. In this medium the drug caused elevated levels of plasma Ca2+ and muscle K+. The simultaneous injection of ergocryptine plus PRL in hyperosmotic media produced an elevated plasma Na+ concentration but a decrease in intracellular Na+ content and concentration.The results suggest that PRL is not critical for the survival of S. gairdneri in fresh water but may still be necessary to maintain body ion concentrations. In hyperosmotic media, however, PRL and GH may be essential for survival and may act on general metabolic processes rather than specific osmoregulatory organs.


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