The effect of Cu super(2+) on osmoregulation in rainbow trout (Oncorhynchus mykiss) assayed by changes in plasma salinity and gill lipid metabolism

Exposure of rainbow trout to Cu super(2+) at levels ranging from 0.1 to 0.8 ppm in brackish water at 13 degree C and subsequent transfer to either clean fresh, brackish or seawater, either at 13-16 degree C or at 4-5 degree C, resulted in: plasma Na super(+) decreased by 8% in fresh water at both temperatures following treatment with 0.8 ppm Cu super(2+); in brackish water it remained normal at 18 degree C, independent of Cu super(2+) treatment, but went up by 8% with 0.8 ppm Cu super(2+) at 4 degree C; in seawater it went up to elevated levels at both temperatures, independent of prior Cu super(2+). Equivalent measurements of the incorporation of [1- super(14)C]acetate into gill phospholipids at 16 degree C showed the same effect of Cu super(2+) in fresh and brackish water, i.e. an enhanced relative incorporation of super(14)C-activity into phosphatidylcholine; in seawater Cu super(2+) apparently induced a marked phospholipid degradation. The incorporation of [1- super(14)C]acetate into gill phospholipids at 5 degree C was not in any case influenced by prior Cu super(2+) treatment.