Table 3.

Gill Na+/K+-ATPase protein levels and molecular activity from Arctic char, rainbow trout and Atlantic salmon acclimated to freshwater or seawater for up to 30 days

Days in freshwater (control) Days in seawater (32‰)
SpeciesIsoform1301241030
Arctic charProtein expression8.1±2.96.7±0.89.3±4.614.8±2.1ND28.8±6.7*,a,b21.4±3.9*,a
Molecular activity703.4±259.4828.7±322.4507.3±114.7311.6±86.0ND1288.3±212.01669.8±278.4b,c
Atlantic salmonProtein expression19.4±1.6**21.0±5.7**NDND22.5±4.174.5±6.6*,a,¶,**46.5±3.0*,a,**
Molecular activity608.3±127.5807.9±274.5NDND639.5±162.6328.9±30.7667.2±93.4
Rainbow troutProtein expression6.6±1.25.9±1.7ND7.3±1.810.1±0.914.3±1.032.7±0.9*,a,c,δ,**
Molecular activity721.0±181.21150.9±434.9ND950.7±215.8807.4±107.21230.1±113.8671.9±81.4
  • Molecular activity: ATP min-1; protein expression: pmol mg-1 protein.

    Values are means ± s.e.m.; sample size for all groups is 5.

    ND, not determined (species not sampled on that day).

  • *,a,b,c,δ Significantly different (P<0.05) from corresponding freshwater 1 day, freshwater 30 day, seawater 1 day, seawater 2 day and seawater 4 day groups, respectively.

  • ** Level is significantly higher (P<0.05) than the corresponding Arctic char and rainbow trout group.