Cyclic AMP: a potent inhibitor of DNA synthesis in cultured arterial endothelial and smooth muscle cells.

The effect of dibutyryl cyclic AMP on DNA synthesis was studied in cultured human umbilical endothelial cells and rat aortic smooth muscle cells. Dibutyryl cyclic AMP (2 X 10(-4) mol/l) inhibited DNA synthesis in both arterial cell types when they were grown in medium supplemented with whole serum or with platelet poor serum, but had no effect in the absence of serum. An effect was seen one hour after the addition of the nucleotide, and the threshold concentration was between 2 X 10(-6) and 2 X 10(-5) mol/l. These results may have relevance to the interaction of platelets and insulin with the arterial wall in the development of atherosclerosis in diabetes.