Interactions between agmatine and polyamine uptake pathways in rat pulmonary artery endothelial cells

Agmatine, a product of arginine metabolism in vascular endothelial cells, i s structurally similar to the natural polyamines, putrescine, spermidine an d spermine. To test the hypothesis that agmatine and polyamines interacted at the level of the polyamine transporter, we determined if polyamines comp eted with agmatine for import and whether interventions modulating polyamin e import exerted coordinate effects on agmatine uptake. Multiple lines of e vidence were obtained to suggest that agmatine enters pulmonary artery endo thelial cells (PAECs) via the polyamine transporter, though its intracellul ar disposition after uptake appears different from the natural polyamines. (C) 2001 Elsevier Science Inc. All rights reserved.