Intracellular ions in salt-sensitive essential hypertension: possible role of calcium-regulating hormones.
To study the blood pressure, ionic, and hormonal responses to chronic dietary salt loading, we measured RBC pHi, Mgi, Nai, and Cai, and compared these with serum levels of Ca-io, 1,25-D, and free levels of PHF in salt-sensitive and salt-insensitive essential hypertension subjects on low and high (200 mEq/day less than UNaV less than 50 mEq/day) dietary salt intakes. As a group, salt loading significantly increased diastolic blood pressure (7.6 +/- /3%), Nai (25.5 +/- /8%) and Cai (27.0 +/- /11%), while Mgi (-14.2 +/- 7%) and pHi (-0.03 +/- /0.01 pH units) fell. Significant changes in pHi, Cai, and Mgi occurred only in SS individuals, who also exhibited elevated levels of 1,25-D and of PHF in association with suppression of Ca-io. Altogether, the pressor response to salt was inversely related to the basal pHi (p less than 0.001), and to the degree of salt-induced suppression of Ca-io (p less than 0.001) and Mgi (p less than 0.001), while being directly related to the basal PHF (p less than 0.001) and to the salt-induced stimulation of 1,25-D (p less than 0.005). We hypothesize that elevated levels of 1,25-D and PHF coordinately shift intracellular cation levels and stimulate cellular calcium uptake from the extracellular space. As such, these calcium-regulating hormones may be responsible, at least in part, for salt-sensitive hypertension.
Resnick
L M
LM
Cardiovascular Center New York Hospital-Cornell Medical Center New York.
Gupta
R K
RK
Lewanczuk
R Z
RZ
Pang
P K
PK
Laragh
J H
JH
D001685:Biological Factors / Q000502:physiology*; D002117:Calcitriol / Q000502:physiology*; D002118:Calcium / Q000378:metabolism; D004573:Electrolytes / Q000378:metabolism*; D006801:Humans; D006973:Hypertension / Q000209:etiology* / Q000378:metabolism; D008274:Magnesium / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology*
D001685:Biological Factors; D004573:Electrolytes; C064505:parathyroid hypertensive factor; D012965:Sodium Chloride; D002117:Calcitriol; D008274:Magnesium; D002118:Calcium