Calcium appetite, blood pressure and electrolytes in spontaneously hypertensive rats

Appetite for solutions of 0.01 M-0.1 M calcium chloride or calcium lactate were assessed using the two-bottle choice technique in spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) normotensive rats fed calcium replete diets. SHR exhibited a marginally increased preference for calcium chloride and a significantly increased preference for calcium lactate (p less than 0.02). In SHR, but not in WKY, 28 days of calcium exposure via the preference test solutions significantly affected systolic blood pressure (p less than 0.03). The group of SHR ingesting calcium chloride had a lower mean systolic blood pressure, and that ingesting calcium lactate had a higher mean systolic blood pressure than the control group receiving no exposure to calcium in preference tests. Blood pressures of individual rats, however, were not related to cumulative milliequivalents of Ca consumed, body weight, whole blood or serum ionized Ca, K or Na concentrations, or total serum calcium. Strain differences in chemosensory sensitivity might play a role in mediating the enhanced self-selection of calcium by SHR.