AJP - Regulatory, Integrative and Comparative Physiology, Vol 250, Issue 2 287-R291, Copyright © 1986 by American Physiological Society
Effects of sodium depletion and angiotensin II on osmotic regulation of vasopressin
C. E. Wade, L. C. Keil and D. J. Ramsay
After alterations in sodium balance, osmotic reactivity of vasopressin
(AVP) release was evaluated in seven conscious dogs during bilateral
intracarotid infusions of hypertonic saline. A low-sodium diet reduced
plasma sodium concentration by 3%; deoxycorticosterone acetate (30 mg/day
for 2 days) elevated the concentration by 1%. Neither treatment altered
resting plasma AVP. Hypertonic intracarotid infusions increased jugular
plasma osmolality by 20 +/- 2 mosmol/kg independent of manipulations.
Plasma AVP values were significantly increased (P less than 0.05) in
sodium-depleted dogs compared with values of the control animals. In
addition, the osmotic reactivity of AVP release was evaluated during
exogenous administration of angiotensin II (ANG II). Intravenous infusion
of ANG II (5 ng . kg-1 . min-1) increased plasma concentration of ANG II
but did not alter concentration of plasma AVP. The slope for the
relationship of jugular plasma osmolality to plasma AVP during hypertonic
intracarotid infusions was significantly increased with intravenous
infusion of ANG II. Sodium depletion and intravenous ANG II potentiate the
relationship of plasma osmolality and plasma AVP when evaluated with
intracarotid hypertonic saline infusions in dogs.
