Table 2.

Predicted Ca²⁺ fluxes and fractional reabsorption

	JCa, pmol·min−1·mm−1 per nephron
Total	Paracellular	Transcellular	%Reabsorption
Base case	2.36	2.02 (1.77 + 0.25)	0.34	69.3
5-fold decrease in$P_{\text{Ca}}^{\text{ap}}$	2.35	2.28 (2.03 + 0.25)	0.07	69.0
5-fold increase in $P_{\text{Ca}}^{\text{ap}}$	2.41	0.86 (0.62 + 0.24)	1.55	70.9
2-fold decrease in $P_{\text{Ca}}^{\text{tj}}$	2.20	1.84 (1.58 + 0.26)	0.36	64.8
10-fold decrease in$P_{\text{Ca}}^{\text{tj}}$	1.40	0.99 (0.70 + 0.29)	0.41	41.2
2-fold increase in $P_{\text{Ca}}^{\text{tj}}$	2.42	2.10 (1.86 + 0.24)	0.32	71.0
10-fold increase in$P_{\text{Ca}}^{\text{tj}}$	2.46	2.16 (1.92 + 0.24)	0.30	72.1
10-fold decrease in$P_{\text{Ca}}^{\text{bm}}$	2.44	2.11 (1.87 + 0.24)	0.33	71.7
10-fold increase in $P_{\text{Ca}}^{\text{bm}}$	2.33	1.99 (1.74 + 0.25)	0.34	68.5
${\sigma }_{\text{Ca}}^{\text{tj}}$ = 0	2.54	2.24 (0.09 + 2.15)	0.30	74.6
${\sigma }_{\text{Ca}}^{\text{tj}}$ = 1	2.33	1.99 (1.99 + 0)	0.34	68.6
Interstitial [Ca2+] at the OM-IM junction = 3.75 mM	2.27	1.93 (1.67 + 0.26)	0.34	66.5
Interstitial [Ca2+] at the OM-IM junction = 2.0 mM	2.40	2.06 (1.81 + 0.25)	0.34	70.4
40% increase in NHE3 and NBC1 expression and 10% increase in Na+-K+-ATPase expression	2.48	2.21 (1.94 + 0.27)	0.27	72.8
CA inhibition in the PT lumen	1.82	1.34 (1.17 + 0.17)	0.48	53.3
90% inhibition of NBC1	1.79	1.21 (1.03 + 0.18)	0.58	52.6
100% inhibition of SGLT2	2.07	1.66 (1.45 + 0.21)	0.41	60.8
100% inhibition of SGLT2 + 15% decrease in SNGFR	1.64	1.34 (1.17 + 0.17)	0.30	56.6

Values in parentheses show decomposition of Ca²⁺ flux (J_Ca) into its diffusive and convective components, respectively. $P_{\text{Ca}}^{\text{ap}}$, $P_{\text{Ca}}^{\text{tj}}$, and $P_{\text{Ca}}^{\text{bm}}$, permeability of apical cell membrane, tight junction, and basement membrane to Ca²⁺; ${\sigma }_{\text{Ca}}^{\text{tj}}$, reflection coefficient of the tight junction to Ca²⁺; [Ca²⁺], Ca²⁺ concentration; OM-IM, outer medulla-inner medulla; CA, carbonic anhydrase; NBC1, basolateral Na⁺-$HC{O}_3^{-}$ cotransporter; SGLT2, Na⁺-glucose cotransporter type 2; SNGFR, single-nephron glomerular filtration rate.