AJP - Regulatory, Integrative and Comparative Physiology, Vol 251, Issue 3 499-R503, Copyright © 1986 by American Physiological Society
Atrial natriuretic peptide levels during acute and chronic saline loading in conscious dogs
F. J. Salazar, J. C. Romero, J. C. Burnett Jr, S. Schryver and J. P. Granger
The purpose of the present study was to determine if acute and chronic
increases in sodium intake by isotonic saline infusion are accompanied by
changes in plasma concentrations of atrial natriuretic peptide (PANP).
Acute saline loading (5% body wt) over a 30-min period in seven conscious
chronically instrumented dogs produced a significant increase in PANP (48
+/- 5 to 119 +/- 24 pg/ml, P less than 0.05). However, chronic and
progressive increments of sodium intake from 5 to 75 to 300 meq/day for 7
days, each by isotonic saline infusion, were examined in the same group of
dogs and had no significant effect on PANP. PANP's were 37 +/- 7, 39 +/- 8,
and 33 +/- 5 pg/ml when sodium intake was changed from 5 to 75 to 300
meq/day, respectively. The increase of sodium intake from 5 to 75 meq/day
produced decreases of plasma renin activity (PRA) (2.5 +/- 0.5 to 1.5 +/-
0.4 ng angiotensin I X ml-1 X h-1, P less than 0.05), plasma aldosterone
concentration (PAC) (19.3 +/- 5.4 to 2.9 +/- 0.4 pg/ml, P less than 0.05),
and urinary excretion of prostaglandin E2 (760 +/- 131 to 320 +/- 58
pg/min, P less than 0.05). Further increase of sodium intake to 300 meq/day
induced decreases of PRA and PAC to undetectable levels and an increase of
urinary excretion of 6-ketoprostaglandin F1 alpha (649 +/- 95 to 1,056 +/-
148 pg/min, P less than 0.05). Before the completion of the study, sodium
intake was decreased from 300 to 75 meq/day.(ABSTRACT TRUNCATED AT 250
WORDS)
