dilator and vasoconstrictor pathways is key to the maintenance of homeostasis and the outcome of disease. In the kidney, prostaglandins (PGs) uphold this balance and regulate renal function: hemodynamics, renin secretion, growth responses, tubular transport processes, and cell fate. With the advent of cyclooxygenase (COX)-2-selective inhibitors, targeted deletions in mice (COX knockouts, PG receptor knockouts), and the discovery of intracrine signaling options for PGs (peroxisome proliferator-activated receptors and perinuclear PGE2 receptors: EP1,3,4), many advances have been made in the study of arachidonic acid metabolites. Although prostacyclin (PGI2) is a major product of the COX pathway, there is very little emphasis on its importance...