Abstract
Male albino rabbits were injected intravenously with large doses of l-norepinephrine daily for 15 days. Morphological alterations in the aortae were insignificant but significant increases in the aortic content of acid muco-polysaccharides and in the uptake of S35-labeled sulfate in acid mucopolysaccharides were observed in the experimental animals in comparison to saline-injected controls. Increase in the carbazole to orcinol ratio of the acid mucopolysaccharides indicated qualitative, as well as quantitative, alterations. The alterations were interpreted as reparative processes in the arterial wall following injury produced by the intense vasoconstrictor action of norepinephrine. This interpretation finds support in the similarity between the observed alterations and those which occur during wound-healing or which follow exposure to a variety of agents known to damage blood vessels.