EFFECT OF ATRIAL-NATRIURETIC-PEPTIDE ON URINE FLOW AND GLOMERULAR-FILTRATION DURING ACUTE RENAL-ALLOGRAFT REJECTION

The effect of exogenous atrial natriuretic peptide (ANP) on urine excr etion and glomerular filtration rate (GFR) during acute renal allograf t rejection was evaluated in a canine model. Eight animals underwent s imultaneous allotransplantation and unilateral native nephrectomy. No preoperative or postoperative immunosuppressive therapy was given. Acu te renal function studies were performed on the allografts and compani on, native kidneys following surgical exposure and mobilization on the third postoperative day. At reexploration, the allografts were found to be grossly enlarged (138 +/- 10 gm.) and contained moderate-to-mark ed perivascular interstitial infiltration. Glomerular filtration rate, determined by measurement of urinary inulin clearance, was significan tly reduced from prenephrectomy baseline values (19 +/- 4 ml. per minu te versus 32 +/- 5 ml. per minute, p <.05). During a 30 minute, intrav enous ANP infusion, allograft urine flow rates increased from 1.4 +/- 0.5 ml. per minute to 3.3 +/- 0.4 ml. per minute (p <.01), and GFR inc reased from 19 +/- 4 ml. per minute to 24 +/- 4 ml. per minute (p <.05 ). During ANP infusion, mean arterial pressure declined from 136 +/- 7 mm. Hg to 116 +/- 7 mm. Hg (p <.05), and the hematocrit remained unch anged. These observations are consistent with previously described, am eliorative effects of ANP in other models of acute ischemic renal inju ry and provide an experimental basis for more extended studies examini ng the potential usefulness of ANP as adjunctive therapy in the treatm ent of acute renal allograft rejection.