Characterization of renal aldosterone receptors in genetically hypertensive rats.
To investigate the aldosterone responsiveness of genetically hypertensive rats, we compared characteristics of renal cytosolic aldosterone receptors from the M strain of stroke-prone, spontaneously hypertensive rats (M-SHRSP) with normotensive Wistar-Kyoto rats (WKY). In M-SHRSP, blood pressure was elevated significantly at 6 wk of age, when their plasma aldosterone concentrations were similar to those in WKY. Decreases in urine volume and sodium excretion were also observed in M-SHRSP. At 10 wk of age, M-SHRSP plasma aldosterone concentrations became significantly higher than those in WKY. On the other hand, the concentration of renal cytosolic aldosterone receptors (type I, aldosterone specific) had already increased at 6 wk of age in M-SHRSP, with no difference in affinity, and levels remained increased thereafter. There were no significant differences in molecular weights or ionic charges of either "activated" or "non-activated" aldosterone-receptor complexes between M-SHRSP and WKY, indicating that the molecular properties were similar in both groups. These results suggest that the increased concentration of aldosterone receptors in the kidneys of M-SHRSP might increase their aldosterone responsiveness and contribute to the development of high blood pressure in these animals.
Horiuchi
M
M
First Department of Internal Medicine, Kinki University School of Medicine, Osaka, Japan.
Nishiyama
H
H
Hama
J
J
Takenaka
T
T
Kondo
H
H
Kino
H
H
Nagata
S
S
Sugimura
K
K
Katori
R
R
D000818:Animals; D001794:Blood Pressure; D002561:Cerebrovascular Disorders; D003600:Cytosol / Q000378:metabolism; D004231:Diuresis; D006973:Hypertension / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D007668:Kidney / Q000378:metabolism*; D008297:Male; D008970:Molecular Weight; D009318:Natriuresis; D011188:Potassium / Q000652:urine; D051381:Rats; D011918:Rats, Inbred SHR / Q000235:genetics; D011921:Rats, Inbred WKY; D018161:Receptors, Mineralocorticoid / Q000737:chemistry / Q000378:metabolism*
D018161:Receptors, Mineralocorticoid; D011188:Potassium