Atrial natriuretic factor in dogs with one-kidney, one-clip Goldblatt hypertension

The temporal changes in the plasma concentration of immunoreactive atrial natriuretic factor (ANF) were studied in dogs (n = 5) before and after renal artery constriction to produce one-kidney, one-clip renovascular hypertension. Three days after renal artery constriction, circulating ANF increased from 34 ± 7 to 344 ± 129 pg/ml (P < 0.05) in association with a 38-mmHg elevation of mean arterial pressure and increases in plasma renin and aldosterone levels. Plasma renin and aldosterone remained elevated for 9 days after renal artery constriction. Arterial pressure stabilized at this elevated level of 35-40 mmHg above base line for the duration of the 4 wk after renal artery constriction. Right atrial filling pressure did not change significantly (P > 0.05) after constriction of the renal artery. This observation suggests that volume expansion with right atrial distention is not the only stimulus for release of ANF in these hypertensive dogs. Plasma ANF remained significantly elevated above base-line levels for 7 days postconstriction even though a twofold decrease from the maximal response of 344 ± 129 pg/ml on day 3 to 168 ± 48 pg/ml on day 7 was observed during this same time interval. Plasma ANF continued to decrease toward prehypertensive levels throughout the remainder of the established phase of the hypertension lasting an addition 21 days of observation. The mechanisms for this observed pattern of plasma ANF are unclear but may involve changes in left atrial distention and stretch as a stimulus for hormone secretion with progression of the hypertension.