[Dietary calcium and arterial hypertension in the rat]

The effect of diets modified with respect to their calcium content was studied in three models of hypertensive rats: mineralocorticoid hypertension, DOCA + saline rats and genetic hypertension, SHR and LH rats. Normocalcemic control diet, was equilibrated in vitamins and contained 0.6 p. 100 Ca, 0.24 p. 100 Na and 0.6 p. 100 K. Low calcium diet with only 0.03 p. 100 Ca was studied in the SHR from 5 to 10 weeks of age. Calcium enriched diets contained 1.3, 1.2 and 2.5 p. 100 calcium respectively for DOCA (6 to 16 weeks), SHR (5 to 44 weeks) and LH (female rats, 4 to 22 weeks). In the SHR low calcium diet enhanced hypertension. At the opposite in the three models, calcium enriched diet lessened hypertension. The effect appeared within 2 weeks and was long lasting. These results clearly establish that in young hypertensive rat a low calcium diet enhances the development of hypertension and confirm earlier works with calcium enriched diets. Experimental and clinical data from other groups leads us to emphasize the importance of alimentary calcium in the hypertensive pathology.