A variety of circulating vasoactive hormones including the biogenic amines have been found to be metabolized on transversing the pulmonary vasculative, and the endothelial cell appears to be the major site for this metabolism. This study seeks to use the vascular endothelial cell in culture as a model of the pulmonary vasculature. The major aim of this project is to characterize the uptake and metabolism of vasoactive amines in cultured endothelium. Specifically: (1) the transport kinetics and metabolism of NE, E, DA and 5-HT with vascular endothelial and smooth muscle (SM) cells will be elucidated; (2) the enzyme profile monoamine oxidase, catechol-O-methyltransferase and phenol sulfotransferase will be determined; (3) the alpha- and beta-adrenergic receptors of the two cell types will be characterized. A primary smooth muscle cell line was isolated from the intimal surface of rabbit aorta, characterized by electron microscopy, and has been used to establish procedures which will soon be used with the endothelial cell line. Recently we have been successful in propagating a pure primary line of endothelial cells. This was accomplished by using two new growth factors, Endothelial Cell Growth Supplement (ECGS) and Human Fibronectin (HFN).