Figure 3.

Segmental accounting of whole kidney K⁺ flows and fluxes in the absence of a regulatory response. Negative or positive transport values correspond to reabsorptive or secretory fluxes. As in Fig. 2. open bars denote normal K⁺ (NK), backslash bars indicate hyperkalemia with active tubuloglomerular feedback (HK + TGF; A2); and forward slash bars shows results when glomerular filtration rate is at its value for normal K⁺ (HK + no TGF; A3). The values shown are those in Table 4. Hyperkalemia per se increases filtered K⁺ and its reabsorption within the proximal convoluted tubule (PCT) and loop of Henle (LOH). Compared with normokalemia, overall K⁺ excretion increases 50% with hyperkalemia, and this is nearly doubled by higher flow. CD, collecting duct; CNT, connecting tubule; DCT, distal convoluted tubule.