[Influence of low calcium diet on the vascular response to angiotensin II in pregnant and non-pregnant rabbit vascular endothelium].

ABSTRACT

This study was conducted in order to evaluate the influence of low calcium intake on the vascular response to angiotensin II (A-II) in pregnant and non-pregnant rabbits. Both were fed on a regular and a low calcium diet, respectively, for a period of at least 25 days. By using the common iliac arterial rings of each of the rabbits, and further classifying the respective arterial rings into those with intact endothelium and those with denuded endothelium, the response to A-II in the rings was compared. A greater degree of refractoriness to A-II was observed in the intact endothelial rings than in the denuded rings regardless of the difference in calcium intake, in both pregnant and non-pregnant rabbits. The refractoriness was however, particularly remarkable in the pregnant arterial rings. Therefore refractoriness to A-II in arterial rings on a low calcium diet is higher than that in the rings on a regular calcium diet regardless of the presence of endothelial cells, in both pregnant and non-pregnant rabbits. It is clear that reduction in the calcium intake results in an increase in the response to A-II, which is caused by increased reactivity of the vascular smooth muscle layer.