ISSN:
1432-2013
Keywords:
Arterial pressure
;
Plasma volume
;
ECFV
;
Interstitial fluid
;
131I-RISA
;
35S-Na2SO4
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract In order to examine the extrarenal roles of aldosterone in cardiovascular homeostasis, the present study compared blood pressure, extracellular fluid volume (ECFV) and plasma volume (PV) in the three following groups: 10 nephrectomized (NX) rats, 10 nephrectomized-adrenalectomized (NX-AX) rats, and 10 NX-AX and aldosterone-treated (NX-AX-A) rats. Two-hundred and fifty micrograms of aldosterone, mixed with sesame oil, was given subcutaneously in the NX-AX-A rats. Mean arterial pressure (MAP) was recorded through previously implanted carotid catheters. ECFV and PV were measured using35S-Na2SO4 and131I-RISA, respectively, 24 h after the operation. These measurements were performed in an unanesthetized and unrestricted condition. MAP gradually increased in the NX group, while a gradual decrease was observed in the other groups. However, MAP was significantly higher in the NX-AX-A group than in the NX-AX group 6 h after the operation and thereafter. Changes in body weight were comparable in the three groups 24 h after the operation. ECFV and PV were both reduced in the NX-AX and NX-AX-A groups as compared to the NX group (P〈0.001 NX-AX vs NX, andP〈0.05 andP〈0.025 NX-AX-A vs NX, respectively). Although ECFV was comparable in the NX-AX and the NX-AX-A groups, PV was significantly greater in the NX-AX-A group than in the NX-AX group (P〈0.05). There was a significant positive correlation between MAP and PV in the rats as a whole (r=0.68,P〈0.001). The area under the curve for plasma aldosterone concentration (PAC), which was estimated in a separate group, was similar in the NX and the NX-AX-A groups, but definitely decreased in the NX-AX group. Thus, it is suggested that aldosterone redistributed ECFV so as to maintain intravascular volume, contributing to attenuation of the fall in blood pressure occuring after adrenalectomy.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00581250
Permalink
