AJP - Renal Physiology, Vol 249, Issue 4 603-F609, Copyright © 1985 by American Physiological Society
Effects of synthetic atrial natriuretic factor in the isolated perfused rat kidney
R. D. Murray, S. Itoh, T. Inagami, K. Misono, S. Seto, A. G. Scicli and O. A. Carretero
It is known that atrial extracts (AE) and synthetic atrial natriuretic
factor (ANF) can increase glomerular filtration rate (GFR) and electrolyte
and water excretion both in vivo and in vitro. It is not clear, however, if
ANF-induced increases in filtered load (increased GFR) are required to
produce natriuresis and diuresis. We perfused isolated rat kidneys with AE
or synthetic ANF at constant pressure in a single-pass system. Extracts of
atrial tissue (1 mg/ml) and high concentrations of ANF (31 and 61 ng/ml)
significantly increased both GFR and electrolyte and water excretion.
During continued infusion of ANF, GFR stabilized at increased levels, but
sodium and water excretion continued to increase. After the termination of
infusions, GFR and potassium excretion returned to control levels, but
sodium and water excretion remained significantly elevated. Infusion of a
low concentration of ANF (3 ng/ml) significantly increased sodium and water
excretion without changing either GFR or potassium excretion. We conclude
that increases in GFR are not a prerequisite for natriuresis and diuresis
in response to ANF, but that increases in GFR can potentiate the response.
Furthermore, our data suggest that ANF increases potassium excretion only
if it increases GFR.
