Abstract
1. Normal and cholesterol-fed rabbits were injected intravenously with 0.6 to 1.0 mc. of S35 (as Na2SO4) and the distribution of the isotope studied by means of autoradiographs. The distribution of S35 was compared with that of stainable mucopolysaccharide.
2. In the normal aorta and pulmonary arteries a close parallelism is seen between the distribution of S35 and that of mucopolysaccharide.
3. The media of the atheromatous aorta, compared to that of the normal aorta, shows a reduced mucopolysaccharide staining and also a reduced isotope incorporation.
4. The intimal lesions show a high mucopolysaccharide content and also a high concentration of isotope, as compared with the media of normal or atheromatous aortas.
5. Fibroblasts and foam cells are situated in relation to the areas of greatest density in the autoradiographs. The deeper necrotic parts of the intima show little S35 incorporation although they contain stainable ground substance.
6. It is suggested that foam cells, as well as fibroblasts, produce the sulfated ground substance.