AJP - Renal Physiology, Vol 250, Issue 3 520-F524, Copyright © 1986 by American Physiological Society
Relationship between renal hemodynamic and natriuretic effects of atrial natriuretic factor
R. E. Sosa, M. Volpe, D. N. Marion, S. A. Atlas, J. H. Laragh, E. D. Vaughan Jr and T. Maack
The degree by which atrial natriuretic factor (ANF)-induced renal
hemodynamic changes account for its natriuretic effect was determined by
early clamp experiments in six anesthetized dogs. After control periods,
perfusion pressure of the left kidney (LK) was reduced to 80-90 mmHg, and
synthetic ANF (auriculin A) was infused intravenously (0.3 micrograms X
min-1 X kg body wt). After recovery, furosemide (F) was administered as a
bolus injection (1 mg/kg body wt). In the right kidney (RK), which served
as a time control, ANF increased (P less than 0.05) glomerular filtration
rate (GFR) 16 +/- 4% and Na excretion (UNa V) 261 +/- 63%, whereas it
decreased urine osmolality (Uosm) 36 +/- 7% without changing free water
clearance. ANF also increased diuresis (V) and kaliuresis (UKV). F produced
qualitatively the same results without changing GFR. In the clamped LK, ANF
failed to increase GFR (22 +/- 4 vs. 26 +/- 4 ml/min), UNaV (30 +/- 9 vs.
33 +/- 11 mueq/min), V, and UKV or to decrease Uosm (841 +/- 97 vs. 840 +/-
114 mosmol/kg H2O). F had similar effects in LK as in RK. The data
demonstrate that the natriuretic effect of ANF is abolished when its renal
hemodynamic actions are impeded. In addition, the results demonstrate that
ANF antagonizes renal vasoconstriction in the dog. The results are
consistent with the view that the ANF-induced natriuresis is due in great
part to an increase in the filtered load of Na into a washed-out inner
medulla.
