Table 2.

Net uptake rates of Cl, Na+ and water, and calculated concentrations of Na+ and Cl and concentrations of unknown cations required for charge balance in fluid absorbed by the intestinal epithelium of different marine or euryhaline fish

Net flux (μl cm−2 h−1, ml kg−1 h−1 or μl g−1 h−1)[Na+] in absorbed fluid (mmol l−1)[Cl] in absorbed fluid (mmol l−1)[Missing cation] (mmol l−1)Osmotic pressure in absorbed fluid (mOsm)
SpeciesH2ONa+Cl
Platichthys flesus1,2.1−0.370.58-274274548
Citharichthys sordidus2,*14.02.33.516425086500
Parophrys vetulus3,*4.4-1.5-341-682
Parophrys vetulus3,§20.20.4100200100400
Anguilla anguilla4,§ (FW)---19926263651
Anguilla anguilla4,§ (SW)---23828042644
Anguilla anguilla4,§ (⅓SW)---26129130642
Salmo gairdneri5,# (⅓SW)1.10.170.2315520954418
Salmo gairdneri5,# (½SW)3.00.790.9926333067660
Salmo gairdneri5,# (SW)4.32.332.825426561141312
Fundulus heteroclitus6, (Posterior, resting)8.4-2.5-136272
Fundulus heteroclitus6, (Posterior, stimulated)−7.4-−3.4-460920 (secretion)
Paralichthys lethostigma7,#3.51.92.1543600571200
Lampetra fluviatilis8, (Anterior intestine)394.499.32115239124478
  • 1 (Grosell et al., 2005); 2 (Grosell et al., 2001); 3 (Grosell et al., 1999); 4 osmotic pressure calculated from reported NaCl concentration in absorbate and cation:anion Gab assuming charge balance in absorbate (Skadhauge, 1974); 5 fish were allowed to drink the exposure medium (Shehadeh and Gordon, 1969); 6 (Marshall et al., 2002); 7 fish were allowed to drink the exposure medium (Hickman, 1968); 8 (Pickering and Morris, 1973).

    FW, freshwater; SW, seawater.

    Predicated osmotic pressure of the absorbed fluid was calculated assuming an osmotic coefficient of 1.

  • Transport by isolated epithelia under asymmetrical conditions in absence of an osmotic gradient.

  • * Transport by isolated epithelia under asymmetrical conditions with osmotic pressure in serosal fluids>mucosal fluids.

  • Transport by isolated epithelia under symmetrical conditions.

  • § In situ perfusion.

  • # Based on drinking rate and intestinal content.