Rise of blood pressure in calcium-deprived pregnant rats

BELIZAN, J.M.; PINEDA, O.; SAINZ, E.; MENENDEZ, L.A.; VILLAR, J.

AMERICAN JOURNAL OF OBSTETRICS AND GYNECOLOGY

MOSBY-ELSEVIER

Año: 1981 vol. 141 p. 163 - 169

0002-9378

It has been postulated that calcium intake is inversely related to blood pressure (BP) in animals and pregnant women. To test this hypothesis, 34 female, 142-day-old Wistar rats were studied prospectively. They were randomly assigned to either a calcium-free diet (16 rats) or a normal diet (18 rats). Weekly measurements of tail systolic BP showed a statistically significant increase in BP in the calcium-free group after 6 weeks of treatment. After 9 weeks on this diet, the animals were mated. Five in the control group and six in the calcium-free group became pregnant. Thereafter, both of these subgroups (pregnant and nonpregnant calcium-free diet) continued with significantly higher BP until they were put to death. Blood samples taken at the end of the study showed significantly lower values of calcium/magnesium (Ca/Mg) ratio, but higher inorganic phosphate in the group consuming a calcium-free diet. Blood pressure during the last 3 weeks of the study was significantly inversely correlated with the blood Ca/Mg ratio and directly correlated with magnesium and inorganic phosphate values. This article supports the hypothesis that a low-calcium diet is associated with high BP in pregnant and nonpregnant female rats.