Chronic saline loading in anoxic renal failure in rats.

The effect of saline loading was compared in two types of experimental acute renal failure--due to i.m. administration of glycerol or to anoxia. In the glycerol model, chronic saline loading for about three weeks prior to the experiment achieved almost complete prevention of the uremia. The blood urea and serum creatinine levels 24 h after the experiment were 44 +/- 2 and 1.3 +/- 0.3 se) mg/dl, respectively. The values for the water-drinking rats were 292 +/- 23 and 3.7 +/- 0.4 mg/dl, respectively. In the anoxic model of acute renal failure, produced by uninephrectomy and contralateral renal artery clamping, chronic saline loading reduced the severity of the resultant uremia, although less impressively than in the glycerol model. The blood urea and serum creatinine 24 h after the experiment were 148 +/- 15 and 1.8 +/- 0.2 mg/dl, respectively. The values for the water-drinking rats were 237 +/- 15 and 2.3 +/- 0.2 mg/dl, respectively. Plasma renin activity was similar in the saline-loaded rats in both the toxic and anoxic models. It seems, therefore, that all known models of acute renal failure have at least a common pathogenic mechanism, which can be influenced by chronic saline loading prior to onset of the disease, and which is most probably not renin dependent. In the anoxic model additional factors, which cannot be counteracted by chronic saline loading, are active in the development of uremia.