Arginine Vasopressin Stimulates Protein Synthesis but Not Proliferation of Cultured Vascular Endothelial Cells

SUMMARYWe previously showed that rat and cow blood vessels contain arginine vasopressin (AVP) of local origin. In the present study, to investigate potential roles for this locally produced peptide. we examined the effects of AVP on growth of cultured vascular endothelial and smooth muscle cells (EC, SMC). Treatment of cultured bovine aortic endothelial (BAE), murine cerebral micro-vascular endothelial (MME), or murine cerebral micro-vascular smooth muscle (MMSM) cells with AVP produced dose-dependent increases in total protein content with maximum increases of 11, 46. and 33% over vehicle-treated controls, respectively. AVP also dose-dependently increased new protein synthesis, as reflected by [H]leucine incorporation into BAE and MME cell protein, with maximal increases of 34 and 249?, respectively. In addition, the AVP-stimulated increase in protein synthesis could be significantly attenuated in both BAE and MME cells by simultaneous addition of a specific AVP VI receptor antagonist. In contrast, AVP did not affect total cell number or DNA synthesis, as reflected by [H]thymidine incorporation, in any cell type. Neither was cell size, as measured by forward light scatter with a fluorescence-activated cell sorter (FACS), changed by treatment with AVP. However, the density of individual cells, as measured by orthogonal light scatter with FACS, was increased by AVP. These data demonstrate that AVP stimulates protein synthesis but not proliferation of cultured vascular EC and SMC and suggest that locally produced AVP may function as a growth factor for these cells.