Atrial natriuretic peptide counteracts angiotensin-II-induced impairment of renal function.

The present study was designed to investigate the effect of atrial natriuretic peptide (ANP) on angiotensin II (AT II)-induced impairment of renal function. Female Sprague Dawley were used in this study. After anesthesia and surgical procedure, animals were infused with AT II at two different doses (group I, 15 micrograms/kg BW/min and group II, 15 ng/kg BW/min) into the left renal artery. Subsequently, alpha-ANP was infused intrarenally (left kidney, LK) at 2 micrograms/kg BW/min. Controls received isotonic saline only. In all cases the right and noninfused kidney (RK) served as control organ. In all animals, AT II led to a dose-dependent compromise of kidney function of the LK. Glomerular filtration rate (GFR) had decreased to 0.16 +/- 0.06 ml/min and 0.41 +/- 0.12 ml/min in group I and II, respectively. Subsequent ANP infusion induced a significant increase of GFR to 0.83 +/- 0.23 (p less than 0.01) and 0.99 +/- 0.20 (p less than 0.05) ml/min in group I and II, respectively. Urinary volume (V) exhibited a slight but not significant increase following AT II infusion. ANP infusion led to a highly significant increase of V in both groups. A less pronounced, but significant increase of absolute sodium excretion of the LK was observed in both groups after AT II infusion. Absolute potassium excretion did not change in this phase of the experiment. ANP infusion induced a significant increase in both parameters. Isotonic saline had no effect on all parameters measured. Mean arterial pressure (MAP) had increased dose dependent following AT II infusion. After ANP infusion, a significant diminution of MAP to basal values was obtained from both groups.(ABSTRACT TRUNCATED AT 250 WORDS)