Na intake, renal renin, and the severity of myohemoglobinuric renal failure in rats.

We have examined the role of dietary Na and renal cortical renin concentration (RCRC) on the severity of glycerol-induced acute renal failure (ARF) in the rat. Na loading (1% NaCl to drink) and Na deprivation (Na-free diet) of 5-6 wk duration decreased and increased RCRC, respectively, with respect to control. As assessed by blood urea nitrogen measured 48 h after glycerol injection, the severity of ARF was inversely related to RCRC. However, this was not a causal relationship. Either 6- or 48-h access to 1% NaCl did not lower RCRC of previously Na-deprived rats, but did decrease the severity of ARF. Conversely, 6- or 48-h access to tap water did not increase RCRC of previously Na-loaded rats, but did increase severity of ARF. A significant inverse correlation was found between severity of ARF and Na excretion prior to glycerol injection, a finding consistent with the hypothesis that solute diuresis has a protective effect.