Fig. 8.

The degree of glomerular hypertension and hyperfiltration is a function of both the primary increase in PT reabsorption and the impaired distal Na regulation or compensation. Loss of distal regulation alone will not cause glomerular hypertension. Increased PT reabsorption alone will cause only a small increase in GFR and glomerular hypertension. But the coupling of the two greatly increases the rise in both GFR and glomerular hydrostatic pressure. [For this simulation, fractional PT Na reabsorption η_pt varied from 0.7 to 0.84; S_P-N,i varied from 1 (normal) to 0 (complete loss of regulation) for all distal segments: LoH, DCT, and CNT/CD.]