Fig. 3.
The NaCl paradox of the diabetic kidney is present in WT mice but absent in A1R–/– mice. Paired GFR measurements were performed in awake WT and littermate A1R–/– mice under the control NaCl diet (1% NaCl, single measurements are shown from the experiments summarized in fig. 1) and after 1 week of low (0.1% NaCl) or high (4%) NaCl intake. Measurements on the 1% NaCl diet were taken at 4 weeks after STZ or vehicle injection. One week later, the mice were switched to a low- or high-NaCl diet. In STZ-diabetic WT mice, switching from control to low or high NaCl intake induced significantly different and opposing responses in GFR, i.e. a rise in response to low NaCl and a fall in response to high NaCl intake. Moreover, the kidney weight was greater in STZ-diabetic WT mice on low versus high NaCl intake. In STZ-diabetic A1R–/– mice, the NaCl paradox of GFR and the greater kidney weight in mice on the low-NaCl diet were not detectable. n = 5–6/group. * p < 0.05.