Metabolism and Distribution of Intravenously Administered d-Aldosterone-l,2-H 3 in the Arteries, Kidneys, and Heart of Dog

Abstract

The initial disappearance of intravenously administered H 3 -d-aldosterone from the plasma was associated with a rapid uptake of the labeled aldosterone in the tissues. The subsequent, slower fall off of plasma aldosterone radioactivity appeared to parallel the biological decay of H 3 -aldosterone in the tissues. H 3 -d-aldosterone attained a maximal level in the kidney, liver, heart, and aorta of dog in five to 15 minutes after the aldosterone injection. During and after the time of peak tissue radioactivity, H 3 -aldosterone radioactivity was higher in the kidney, liver, heart, and thoracic aorta than in the plasma. No consistent relationship was observed between the H 3 -aldosterone uptake and the salt, water, and acid mucopolysaccharide content of different portions of the aorta. Subcellular fractionation of the tissues indicated that most of the H 3 -aldosterone taken up by the tissues was present in the supernatant fraction and not bound to subcellular particles. Radioautography revealed a high concentration of H 3 -aldosterone along the cell walls of the convoluted tubular cells and along the walls of the glomerular capillaries, arterioles, and Bowman's capsule. In the heart H 3 -aldosterone localized along the cell walls of the heart muscle cells, whereas in the aorta the hormone appeared to accumulate over the cytoplasm of the smooth muscle cells. The uptake and distribution of H 3 -aldosterone in the tissues were not altered by pretreatment with the aldosterone antagonist, spironolactone.