Figure 6.

Glomerular hemodynamic effects of Na-glucose cotransporter (SGLT2) inhibitor superimposed on a model of tubuloglomerular feedback (TGF), which incorporates effects on pre- and postglomerular resistances. Idealized TGF curves are shown for glomerular filtration rate (GFR) and PGC. The PGC curve lies to the right of the GFR curve owing to differences in the way that pre- and postglomerular resistances react across the range of inputs, as shown in the bottom portion of the figure. Within a group of nephrons, the position of operating points along the respective TGF curves will form a distribution. The figure shows the effects on GFR and PGC when identical increases in macula densa delivery are imposed by SGLT2 inhibitor for two nephrons drawn from this distribution (nephrons A and B). For nephron A, the TGF response to SGLT2 blocker included a large decrease in GFR and small decrease in PGC. For nephron B, there was a smaller decline in GFR and a larger decline in PGC. The inverse relationship between decreases in whole kidney GFR and decreases in average PGC for that animal is expected if animals with the smaller decreases in GFR yet larger decreases in PGC had more nephrons operating near the elbow of their respective TGF curves and vice versa.