title: The extrarenal effects of aldosterone on the distribution of extracellular fluid in conscious adrenalectomized-nephrectomized rats.
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 using 35S-Na2SO4 and 131I-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 the NX-AX-A groups as compared to the NX group (P less than 0.001 NX-AX vs NX, and P less than 0.05 and P less than 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 less than 0.05). There was a significant positive correlation between MAP and PV in the rats as a whole (r = 0.68, P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000315:Adrenalectomy; D000450:Aldosterone / Q000097:blood / Q000502:physiology*; D000818:Animals; D001794:Blood Pressure; D003243:Consciousness; D005110:Extracellular Space / Q000378:metabolism*; D008297:Male; D009392:Nephrectomy; D009994:Osmolar Concentration; D010953:Plasma Volume; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors; D014018:Tissue Distribution
chemical_list: D000450:Aldosterone