Evidence supporting a physiological role for proANP-(1–30) in the regulation of renal excretion
JOHN R. DIETZ; DIONNE Y. SCOTT; CAROL S. LANDON; AND STANLEY J. NAZIAN
05/22/2014
Dietz, John R., Dionne Y. Scott, Carol S. Landon, and Stanley J. Nazian. Evidence supporting a physiological role for proANP-(1–30) in the regulation of renal excretion. Am J Physiol Regulatory Integrative Comp Physiol 280: R1510–R1517, 2001.—The experiments, performed in pentobarbital sodium-anesthetized rats, consisted of a 1-h equilibration period followed by two 30-min control periods. Subsequently, synthetic rat pro atrial natriuretic peptide (ANP) [proANP-(1–30)] (n 5 8) was given as a bolus of 10 mg in 1 ml of 0.9% saline followed by an infusion at 30 ng/min (20 ml/min) for six additional periods. Control rats (n 5 6) received only 0.45% saline in the appropriate volumes. Mean arterial pressure, renal blood flow, and glomerular filtration rate did not change significantly in either group during the proANP-(1–30) infusion. Urine flow and potassium excretion increased ;50% in the proANP-(1–30)-infused group only (P , 0.05). Sodium excretion and fractional excretion of sodium, expressed as the change from their own baselines, were significantly increased by the proANP-(1–30) infusion (P , 0.05), whereas cGMP excretion was similar in both groups. These results suggest that the rat sequence of proANP-(1–30) produces a natriuresis in the rat independent of changes in hemodynamics and renal cGMP production. In a second study, rats (n 5 8) were prepared as above and pretreated with 0.4 ml iv of rabbit serum containing an antibody directed against proANP-(1–30) (anti-proANP group). The rats were volume expanded with 3 ml of 6% albumin in Krebs and observed for 3 h to determine if the anti-proANP would attenuate the responses to volume expansion. Control rats (n 5 7) received 0.4 ml of normal rabbit serum. The elevation in potassium excretion in response to volume expansion was significantly attenuated in the antiproANP group (P , 0.05). Sodium excretion and urine flow responses also tended to be reduced but not significantly. These results suggest that in the rat, proANP-(1–30) plays a physiological role in regulating renal excretion.