Table 1.

Net mean uptake rates of Na+ and Cl across the intestinal epithelium in eight marine teleost fish

SpeciesNet Cl fluxNet Na+ fluxΔNa+-ClNet HCO3 flux% of Cl flux
Parophrys vetulus1,§0.40.2−0.2−0.250
Citharichthys dordidus2,*3.52.3−0.9−0.926
Platichthys flesus3,*1.00.8−0.2−0.330
Opsanus beta4,0.70.3−0.4−0.571
Platichthys flesus5,0.6−0.4−1.0−0.350
Anguilla anguilla6,3.00.9−2.1-(70)
Pseudopleuronectes americanus7,3.11.2−1.9-(61)
Pseudopleuronectes americanus8,5.52.0−2.5-(45)
Platichthys flesus9,6.52.2−4.3-(66)
Platichthys flesus10 (FW)15.89.1−6.7-(42)
Platichthys flesus10 (SW)26.618.5−8.1-(30)
Platichthys flesus11 (FW)1.71.1−0.6-(35)
Platichthys flesus11 (SW)2.51.7−0.8-(32)
Platichthys lethostigma 12 2.11.9−0.2-(10)
Gillichthys mirabilis13,2.51.3−1.2-(48)
  • Flux values are in mequiv kg−1 h−1 orμ equiv cm−2 h−1.

    FW, freshwater; SW, seawater.

    ΔNa+-Cl transport shows the difference between Na+ and Cl net absorption. For four of the eight species represented, net HCO3 secretion (negative net flux) was also determined. For these four species, the magnitude of net HCO3 secretion is similar to theΔ Na+-Cl transport, suggesting that Cl uptake, in excess of Na+ uptake, is driven by HCO3/Cl exchange. The column labeled `% of Cl flux' shows the fraction of Cl uptake that may be accounted for by anion exchange based on simultaneous measurements of HCO3 secretion. Values in parentheses are calculated assuming thatΔ Na+-Cl can be accounted fully for by anion exchange.

    1 (Grosell et al., 1999); 2 (Grosell et al., 2001); 3 (Grosell and Jensen, 1999); 4 (M.G., unpublished); 5 (Grosell et al., 2005); 6 (Marvao et al., 1994); 7 (Field et al., 1980); 8 (Musch et al., 1990); 9 (Mackay and Lahlou, 1980); 10 (Smith et al., 1975); 11 (Gibson et al., 1987); 12 (Hickman, 1968); 13 (Loretz, 1996).

  • 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.