Arterial homeostasis is dictated by hemodynamics and intercellular communications. Therefore, the present study exposed vascular cells to mechanical forces and conditioned medium to determine the impact of intracellular communication on cell responses. Endothelial cells exposed to flow and flow-conditioned medium demonstrated the most significant up regulation of COX-2 ( p < 0.01), ecNOS ( p < 0.01), and PDGF-B ( p < 0.05) mRNA. When exposed to pressure and control medium, endothelial cells expressed COX-2 ( p < 0.01), ecNOS ( p < 0.01), and PDGF-B ( p < 0.01) mRNA to a lesser extent than cells exposed to flow and control medium. In addition, cell growth studies in the presence of flow- and pressure-conditioned medium revealed decreased ( p < 0.05) endothelial cell growth and increased ( p < 0.05) smooth muscle cell growth. Ultimately, understanding the effects of chemical mediators released by vascular cells under physiological and pathological conditions will aid in elucidating the development and progression of atherosclerosis.