Calcium supplementation in salt-dependent hypertension.
To clarify the mechanism of the antihypertensive effect of oral Ca loading, we studied the effect of Ca supplementation on salt-induced blood pressure elevations in patients with essential hypertension and DOCA-salt hypertensive rats. When the diet was changed from low to high salt (300 mEq/day), the percent increase in mean blood pressure was smaller (p less than 0.01) in the Ca-supplemented (2,160 mg/day) patients than in the Ca-restricted (250 mg/day) ones. Oral Ca loading resulted in a smaller weight gain, a greater urinary sodium excretion, and an increase in red cell Mg. In the experimental study, high Ca (4% CaCl2) intake attenuated the blood pressure elevation in DOCA-salt-treated rats, accompanied with an increase in urinary sodium excretion, with the resultant attenuation in intra- and extracellular sodium retention. The decrease in catecholamine contents of hearts was improved, and a higher survival rate was observed in Ca-supplemented DOCA-salt rats. The results suggest that Ca supplementation may prevent a rise in BP in salt-dependent hypertension by inducing natriuresis with the resultant attenuation in sodium retention. The altered intracellular Mg level in hypertensive patients and the normalization of enhanced sympathetic nervous activity in DOCA-salt rats may, in part, be involved in its mechanism.
Saito
K
K
Department of Internal Medicine, Sanda Municipal Hospital, Japan.
Sano
H
H
Furuta
Y
Y
Yamanishi
J
J
Omatsu
T
T
Ito
Y
Y
Fukuzaki
H
H
D000328:Adult; D000368:Aged; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D002136:Calcium, Dietary / Q000008:administration & dosage*; D003900:Desoxycorticosterone / Q000494:pharmacology; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009318:Natriuresis; D051381:Rats; D011921:Rats, Inbred WKY; D012965:Sodium Chloride / Q000008:administration & dosage*
D002136:Calcium, Dietary; D003900:Desoxycorticosterone; D012965:Sodium Chloride