The Effect of Seventy-Two-Hour Continuous Infusion of Long-Acting Natriuretic Peptide on Acute Ischemic Renal Failure in the Rat

OBJECTIVES: Atrial natriuretic peptide (ANP(1-28)) protects the kidneys against acute renal failure in animals; however, its use in humans has been disappointing. Long-acting natriuretic peptide (LANP(1-30)) has natriuretic and diuretic actions similar to ANP(1-28), but it has a longer half-life and a different receptor site. Therefore, this study's aim was to determine if LANP(1-30) has better renal protection than ANP(1-28), which may make it useful in the treatment of acute renal failure. SUBJECTS/METHODS: Three groups of male Sprague-Dawley rats were used, each with a body weight between 250-300 gm. Group 1 (ischemia only, n = 6) had a right nephrectomy followed by 30 minutes of left renal pedicle clamping. Group 2 (LANP Peptide treated, n = 7) had renal ischemia similar to Group 1, followed by an intraperitoneal bolus of 10 microg of LANP(1-30) and the placement of mini-osmotic pumps delivering LANP(1-30) at a rate of 1 microg/hr for 72 hours. Group 3 (controls, n = 6) was used to measure the baseline creatinine level and had no renal ischemia or surgery. RESULTS: Seventy-two hours post-renal ischemia, the weight loss in the ischemia group was similar to the peptide treated group (7.65 +/- 1.14% and 10.03 +/- 0.9% body weight loss, respectively, p = 0.126). The ischemia group had significantly higher creatinine levels compared to the controls (66.3 +/- 5.3 versus 30.1 +/- 0.9 micromol/L, p = 0.002). The peptide-treated group had higher creatinine (174.1 +/- 77.8 versus 66.3 +/- 5.3 micromol/L, p = 0.035) and LANP(1-30) levels (673.14 +/- 69.64 versus 45.83 +/- 8.45 pg/mL, p = 0.001) than the ischemia group. CONCLUSION: Prolonged use of LANP(1-30) has no renal protective effect.