Effect of dietary calcium on the development of hypertension and hypertensive vascular lesions in DOCA-salt and two-kidney, one clip hypertensive rats.
OBJECTIVE
To examine the effect of modest changes in dietary calcium on systolic blood pressure (SBP) and myocardial and renal vascular lesions in Sprague-Dawley rats.


METHODS
Regular- (0.4%, by weight), high- (0.8%) or low-calcium (0.24%) diets were fed to normotensive control, deoxycorticosterone acetate (DOCA)-salt and two-kidney, one clip (2-K, 1C) hypertensive rats for 8 weeks.


METHODS
Tail-cuff SBP and metabolic balance were measured once a week. At the end of the study the kidneys and hearts were collected for histological study.


RESULTS
Dietary calcium had no effect on SBP in the DOCA-salt rats, but loading with calcium accelerated the rise in SBP in 2-K,1C rats (P < 0.01, high- versus regular-calcium diet). The high-calcium diet reduced the percentage medial area of intramyocardial arteries in the DOCA-salt and 2-K,1C hypertensive rats. The DOCA-salt rats on the low-calcium diet had a higher renal vascular lesions score than those on the regular- or high-calcium diet (P < 0.05).


CONCLUSIONS
A high-calcium diet appears to prevent intramyocardial vascular wall thickening in DOCA-salt and 2-K,1C hypertensive rats, and a low-calcium diet aggravates renal vascular lesions in DOCA-salt hypertensive rats. These effects are not related simply to changes in blood pressure.
Department of Medicine, St George Hospital, University of New South Wales, Kogarah, Australia.
D T
DT
Liu
I
I
Birchall
T
T
Hewitson
P
P
Kincaid-Smith
J A
JA
Whitworth
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002136:Calcium, Dietary / Q000008:administration & dosage / Q000009:adverse effects*; D003900:Desoxycorticosterone; D004573:Electrolytes / Q000378:metabolism; D006321:Heart / Q000187:drug effects; D006973:Hypertension / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D006978:Hypertension, Renovascular / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D007668:Kidney / Q000187:drug effects / Q000473:pathology; D009206:Myocardium / Q000473:pathology; D009929:Organ Size / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley
D002136:Calcium, Dietary; D004573:Electrolytes; D003900:Desoxycorticosterone