AJP - Heart and Circulatory Physiology, Vol 244, Issue 2 259-H265, Copyright © 1983 by American Physiological Society
Plasma vasopressin in rats: effect of sodium, angiotensin, and catecholamines
D. B. Brunner, M. Burnier and H. R. Brunner
A radioimmunoassay was set up to measure plasma arginine vasopressin levels
(AVP). Characteristics of the assay include a sensitivity to 0.25 pg, high
specificity of the antibody, mean recovery of added unlabeled arginine
vasopressin of 80%, and an interassay coefficient of variation of 7.6%.
This assay was used to investigate the influence of various factors on
plasma vasopressin levels in a total of 121 awake male rats. Blood samples
obtained in Wistar rats via an indwelling arterial catheter yielded results
similar to those following decapitation, i.e., 1.27 +/- 0.26 vs. 1.68 +/-
0.39 pg/ml. Forty-eight hour dehydration markedly increased plasma AVP to
21.8 +/- 2.39 pg/ml. AVP was less than 0.5 pg/ml in Brattleboro rats. Low
and high sodium intake, angiotensin II infusion (10 and 30 ng/min), and
converting enzyme inhibition by captopril (100 mg/kg) did not alter plasma
AVP. During norepinephrine infusion (250 ng/min) plasma AVP rose to 5.28
+/- 1.29 pg/ml, whereas it tended to fall with isoproterenol infusion (10
ng/min). Plasma AVP was slightly higher in spontaneously hypertensive rats
than in Wistar-Kyoto controls.
