Effects of environment on tissue norepinephrine concentration in chum salmon (Oncorhynchus keta)

To investigate the effects of environment on tissue norepinephrine (tNE) le vels of fish, we examined tNE concentrations in the adult chum salmon (Onco rhynchus keta) from fresh water (FW) and from sea water (SW). Plasma norepi nephrine (pNE) and tNE of 15 organs, including the gill, heart, liver, aort a, spleen, stomach, jejunum, colon, brain stem, cerebrum, muscle, bone, sex ual organ and kidney (head and body), were determined in river and sea salm on by high performance pressure liquid chromatography with electrochemical detection. tNE concentrations of all organs except the gill of sea salmon w ere significantly lower in comparison with those in river salmon. The pNE c oncentration was higher in sea salmon than in river salmon of male but not female. In river salmon, tNE concentrations of 12 organs of females were hi gher than those of male, whereas in sea salmon, there was no significant di fference in tNE concentrations of all organs except the liver between male and female. Plasma osmolality and sodium concentration were higher in sea s almon than in river salmon. These results indicate that tNE concentrations in most organs of salmon in a SW environment are significantly decreased co mpared with those in a FW environment, and that tNE concentrations are high er in female salmon than in male salmon in a FW environment but not in a SW environment. J. Exp. Zool. 284:107-111, 1999. (C) 1999 Wiley-Liss, Inc.