Table 8.

End superficial distal convoluted tubule solute concentrations and cotransporter fluxes: aldosterone (B1) and combined aldosterone plus reduced NCC (B2)

Case B1	Lumen	Cell	Interstitium
PD, mV	−8.7	−89.2
Concentrations, mM
Na+	35.1	10.4	142.8
K+	7.0	144.0	5.5
Cl−	35.2	18.4	117.5
${\text{HCO}}_3^{-}$	4.0	9.0	26.9
CO2	1.8	1.8	1.8
${\text{HPO}}_4^{2-}$	1.4	9.2	1.9
${\text{H}}_{\text{2}}{\text{PO}}_{\text{4}}^{-}$	4.7	9.0	0.6
Urea	11.7	5.1	4.7
${\text{NH}}_4^{+}$	4.7	1.4	0.5
Imp		92.1
pH	6.29	6.81	7.28
Cotransporter fluxes, nmol/s/cm2
NCC(Na)	4.37
NHE2(Na)	0.52
NHE2(H)	−0.31
NHE2(NH4)	−0.10

Case B2	Lumen	Cell	Interstitium
PD, mV	−10.4	−88.3
Concentrations, mM
Na+	57.3	8.1	143.0
K+	6.6	147.3	5.5
Cl−	61.3	12.8	117.4
${\text{HCO}}_3^{-}$	1.9	8.9	27.1
CO2	1.8	1.8	1.8
${\text{HPO}}_4^{2-}$	0.7	10.3	1.9
${\text{H}}_{\text{2}}{\text{PO}}_{\text{4}}^{-}$	5.0	10.0	0.6
Urea	10.4	5.0	4.7
${\text{NH}}_4^{+}$	5.8	0.9	0.4
Imp		94.7
pH	5.97	6.81	7.29
Cotransporter fluxes, nmol/s/cm2
NCC(Na)	1.86
NHE2(Na)	0.92
NHE2(H)	−0.38
NHE2(NH4)	−0.46

NCC, NaCl cotransporter; NHE2, Na⁺/H⁺ exchanger isoform 2; Imp, cytosolic impermeant.