AJP - Regulatory, Integrative and Comparative Physiology, Vol 258, Issue 1 77-R81, Copyright © 1990 by American Physiological Society
Atrial appendectomy reduces ANF but not sodium excretion in acute vasopressin hypertension
R. S. Zimmerman, R. W. Barbee, A. Martinez, A. A. MacPhee and N. C. Trippodo
Department of Endocrinology, Ochsner Clinic, New Orleans, Louisiana.
The present study was designed to determine whether atrial appendectomy
would decrease the sodium excretion associated with pressor doses of
arginine vasopressin (AVP) infusion in rats by decreasing circulating
levels of atrial natriuretic factor (ANF). Ten to 21 days after either sham
(n = 9) or bilateral atrial appendectomy (n = 13) AVP (19 ng.kg-1.min-1)
was infused for 90 min in anesthetized Sprague-Dawley rats. Atrial
appendectomy decreased circulating ANF levels from 469 +/- 70 pg/ml in
sham-operated animals to 259 +/- 50 pg/ml (P less than 0.05) in
atrial-appendectomized animals after 90 min of AVP infusion. Despite a
reduction in circulating levels of ANF, sodium excretion, potassium
excretion, and urine flow increased and were not affected by bilateral
atrial appendectomy. Glomerular filtration rate and mean arterial pressure
significantly increased in both groups of rats. The present study supports
non-ANF factors such as increases in renal perfusion pressure and/or
glomerular filtration rate as potential mechanisms in AVP-induced
natriuresis.
