Figure 3.

Na-H exchange in intestinal epithelial cells in obesity. A–C) NHE3, defined as 5-(N-ethyl-N-isopropyl)amiloride–sensitive and proton gradient–driven ²²Na uptake, was unchanged in BBMVs from OZRs compared with LZRs (A). This observation was consistent in the BBMV preparations in TOM (B) and obese humans (C). D–F) Western blot analysis showed that villus-cell NHE3 protein levels remained unchanged in BBM between OZRs and LZRs (D), TOM and C57BL/6 (E), and obese and normal humans (F). G–I) Immunofluorescence studies for NHE3 expression in Zucker rats followed by densitometric analysis confirmed that NHE3 (red) was unaltered between LZRs (G) and OZRs (H) in the BBM of small-intestinal villus cells, and densitometric quantification of both (I) showed unchanged NHE3 as well. For all experiments, n represents different studies performed with intestinal cells isolated from different host each time. In D–F, the upper panel is a representative Western blot experiment performed at least 3 times and quantitated in the lower panels. A representative experimental pictograph is shown in G and H, and quantitation of 5 such experiments is shown in I; n = 4. P < 0.01 in graphs.