Figure 1. Physiological parameters of a rat model of early hypokalemia-induced NDI.

Urinary fractional excretion of potassium (A), serum potassium (B), urine volume (C), and urine osmolality (D) were measured in rats receiving either a normal chow diet (■, n = 7) or a potassium-free diet (NK; □, n = 7) for 1, 2, and 3 days. The units for urinary fractional excretion of potassium (shown as %) are a ratio of urinary:plasma potassium concentration normalized to that of urinary:plasma creatinine concentration. (E) Immunoblotting of inner medullary proteins from control rats (+, ■, n = 7) and potassium-deprived rats (–, □, n = 7) after 1 day of potassium deprivation. The two bands of AQP2 (29 kDa non-glycosylated and 37 kDa glycosylated isoforms) are indicated with arrows.