Mn++ stimulates 3H-inositol incorporation into membrane phosphatidylinositol in cultured aortic smooth muscle cells from WKY and SHR rats. The stimulation does not occur with other cations and appears to result from activation of enzymatic exchange of free inositol with the headgroup inositol of membrane PI. The Mn++-stimulated 3H-inositol incorporation is lower in SHR cells than in WKY cells suggesting a biochemcial defect in SHR aortic smooth muscle cells. This defect may reside in the endoplasmic reticulum the smooth muscle cells.
