Variations in endogenous phosphodiesterase activator content of rat aorta

The variations with age and blood pressure in the cyclic nucleotide phosphodiesterase activator content of rat aorta were studied. Activator content increased with age and was less in mineralocorticoid-hypertensive than in control rats. These variations were more pronounced in the particulate than in the soluble fraction of aorta. The data do not demonstrate any relationship between the activator level and blood pressure, but they suggest that the activator may modulate cyclic nucleotide metabolism in rat aorta.