AJP - Heart and Circulatory Physiology, Vol 243, Issue 3 365-H370, Copyright © 1982 by American Physiological Society
Concentrations of ionic and total calcium in plasma of four models of hypertension
G. L. Wright and G. O. Rankin
The levels of ionic calcium in whole blood obtained from female
Sprague-Dawley (SDR). Wistar-Kyoto (WKY), and spontaneously hypertensive
(SHR) rate tended to decrease between 5 and 13 wk of age. During this
interval the plasma total calcium levels of each strain remained stable,
indicating an increase in the binding or complexing of endogenous calcium
with maturation. The ionic calcium levels of WKY were lower than those of
SDR, while SHR levels were below those of the WKY and SDR strains. Neither
the one-kidney, one-clip (1KHT) nor the two-kidney one-clip (2KHT)
renovascular models of hypertension showed evidence of an alteration in
blood ionic or total calcium concentrations compared with sham-operated
controls. The ionic calcium levels of blood from
deoxycorticosterone-treated (DOCA/saline) hypertensive rats were
significantly reduced from those of sham-operated controls but were similar
to values recorded for normotensive uninephrectomized controls. Each of the
four models of hypertension studied and the normotensive uninephrectomized
control group demonstrated some degree of reduction in the in vitro binding
or complexing of exogenous calcium. The results indicate that the
spontaneous, renovascular, and mineralocorticoid forms of hypertension
examined were accompanied by some disturbance in extracellular calcium
homeostasis. It is unlikely, however, that the alterations observed are
primary causal factors in the maintenance of high blood pressure.
