The Company of Biologists

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⁻¹h⁻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)
Species	H₂O	Na⁺	Cl⁻			[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)
Platichthys flesus¹,^{^†}	2.1	−0.37	0.58	-	274	274	548
Citharichthys sordidus²,^{^*}	14.0	2.3	3.5	164	250	86	500
Parophrys vetulus³,^{^*}	4.4	-	1.5	-	341	-	682
Parophrys vetulus³,^{^§}	2	0.2	0.4	100	200	100	400
Anguilla anguilla⁴,^{^§}(FW)	-	-	-	199	262	63	651
Anguilla anguilla⁴,^{^§}(SW)	-	-	-	238	280	42	644
Anguilla anguilla⁴,^{^§}(⅓SW)	-	-	-	261	291	30	642
Salmo gairdneri⁵,^{^#}(⅓SW)	1.1	0.17	0.23	155	209	54	418
Salmo gairdneri⁵,^{^#}(½SW)	3.0	0.79	0.99	263	330	67	660
Salmo gairdneri⁵,^{^#}(SW)	4.3	2.33	2.82	542	656	114	1312
Fundulus heteroclitus⁶,^{^‡}(Posterior, resting)	8.4	-	2.5	-	136		272
Fundulus heteroclitus⁶,^{^‡}(Posterior, stimulated)	−7.4	-	−3.4	-	460		920 (secretion)
Paralichthys lethostigma⁷,^{^#}	3.5	1.9	2.1	543	600	57	1200
Lampetra fluviatilis⁸,^{^‡}(Anterior intestine)	39	4.49	9.32	115	239	124	478

	Net flux (μl cm⁻² h⁻¹, ml kg⁻¹ h⁻¹ or μl g⁻¹h⁻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)
Species	H₂O	Na⁺	Cl⁻			[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)
Platichthys flesus¹,^{^†}	2.1	−0.37	0.58	-	274	274	548
Citharichthys sordidus²,^{^*}	14.0	2.3	3.5	164	250	86	500
Parophrys vetulus³,^{^*}	4.4	-	1.5	-	341	-	682
Parophrys vetulus³,^{^§}	2	0.2	0.4	100	200	100	400
Anguilla anguilla⁴,^{^§}(FW)	-	-	-	199	262	63	651
Anguilla anguilla⁴,^{^§}(SW)	-	-	-	238	280	42	644
Anguilla anguilla⁴,^{^§}(⅓SW)	-	-	-	261	291	30	642
Salmo gairdneri⁵,^{^#}(⅓SW)	1.1	0.17	0.23	155	209	54	418
Salmo gairdneri⁵,^{^#}(½SW)	3.0	0.79	0.99	263	330	67	660
Salmo gairdneri⁵,^{^#}(SW)	4.3	2.33	2.82	542	656	114	1312
Fundulus heteroclitus⁶,^{^‡}(Posterior, resting)	8.4	-	2.5	-	136		272
Fundulus heteroclitus⁶,^{^‡}(Posterior, stimulated)	−7.4	-	−3.4	-	460		920 (secretion)
Paralichthys lethostigma⁷,^{^#}	3.5	1.9	2.1	543	600	57	1200
Lampetra fluviatilis⁸,^{^‡}(Anterior intestine)	39	4.49	9.32	115	239	124	478

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.

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