Low plasma and renal tissue levels of L-arginine in rats with obstructive nephropathy

Rats with bilateral ureteral obstruction (BUO) of 24 hours duration had significantly lower plasma levels of L-arginine than at baseline (P < 0.0001), but no significant changes occurred in sham-operated rats (SOR). In contrast, rats with bilateral nephrectomy had greater plasma levels of L-arginine four hours (P < 0.03) and 24 hours (not significant) after nephrectomy than at baseline. Total body irradiation prior to obstruction prevented the decrease in plasma levels of L-arginine in rats with BUO but had no effect on these values in SOR. Renal tissue levels of L-arginine were 20% lower in rats with BUO than in SOR. Total body irradiation prior to BUO resulted in greater renal tissue levels of L-arginine than occurred in nonirradiated rats with BUO (P < 0.002). Total body irradiation did not effect renal tissue levels of L-arginine in SOR. Excretion of reactive nitrogen intermediates in urine (URNI), indicative of L-arginine metabolism through the nitric oxide pathway, was lower in rats with BUO than in SOR (P < 0.001). Proximal tubules from rats with BUO synthesized less L-arginine than those from SOR (P < 0.02). The results indicate that: (1) decreased levels of L-arginine in plasma and renal tissue of rats with BUO correlate with leukocyte infiltration of the kidney, and (2) decreased synthesis of L-arginine occurs in proximal tubules of rats with BUO when compared to tubules from SOR.(ABSTRACT TRUNCATED AT 250 WORDS)