Table 5.
JPO4, pmol·min−1·mm−1 per nephron |
|||||
---|---|---|---|---|---|
Filtered Load, pmol/min per nephron | %Reabsorption | Net | Transcellular | Paracellular | |
Base case | 78.0 | 79.2 | 5.62 | 7.14 | −1.52 |
75% inhibition of Na+-PO4 transporters | 78.0 | 54.7 | 3.88 | 2.69 | +1.19 |
90% inhibition of Na+-PO4 cotransporters | 78.0 | 46.2 | 3.27 | 1.26 | +2.01 |
NHE3 inhibition* | 78.0 | 94.8 | 6.73 | 9.92 | −3.19 |
NHE3 inhibition* and 75% inhibition of Na+-PO4 cotransporters | 78.0 | 55.5 | 3.93 | 4.16 | −0.23 |
NHE3 inhibition* and 90% inhibition of Na+-PO4 cotransporters | 78.0 | 38.6 | 2.73 | 1.97 | +0.76 |
20% reduction in SNGFR | 62.4 | 67.1 | 3.81 | 4.47 | −0.66 |
20% reduction in SNGFR, NHE3 inhibition* and 75% inhibition of Na+-PO4 cotransporters | 62.4 | 47.7 | 2.70 | 2.59 | +0.11 |
20% reduction in SNGFR, NHE3 inhibition* and 90% inhibition of Na+-PO4 cotransporters | 62.4 | 35.8 | 2.03 | 1.22 | +0.81 |
JPO4, flux of PO4 (+ ); NHE3, Na+/H+ exchanger type 3; SNGFR, single-nephron glomerular filtration rate. Fractional inhibition of Na+-PO4 cotransporters NaPi-IIa, NaPi-IIc, and PiT-2 is taken to be the same.
Parathyroid hormone is assumed to reduce basal expression of NHE3 and Na+-K+-ATPase by 75% and 25%, respectively.