K-TROUT GILL AND LIVER-TISSUE, CELL-SUSPENSIONS AND CULTURED-CELLS( BALANCE IN RAINBOW)

Both intact gill and liver tissue from rainbow trout accumulated K+, a s determined by Rb-86(+) uptake, a process largely inhibited by ouabai n, indicating the presence of functional NaKATPase. Cell suspensions, produced by disaggregation of gill or liver tissues, accumulated very little K+ compared to tissues (less than 10%). Disaggregation resulted in depolarisation af cells with loss of intracellular K+ and although NaKATPase, as measured by Rb-86(+) uptake rate, remained functional a nd inhibitable by ouabain, the activity was insufficient to replace th e rapid K+ loss. While attached, cultured gill and liver cells showed normal K+/Na+ ratios and NaKATPase activity, but release from the subs tratum resulted fn depolarisation and rapid K+ loss as seen in cell su spensions. These results suggest that care is required in interpreting ionic regulatory and other results from cell suspensions and that fur ther research should be directed towards systems where cells can maint ain normal ionic balance.