. Total peripheral resistance (r = 0.41, P<0.02) was linked to erythropoietin in established but not in borderline hypertension. However, erythropoietin was inversely correlated with renal plasma flow in both established and borderline hypertension (r = -0.33, P<0.05, and r = -0.34, P<0.05 respectively). In normotensive subjects, in contrast, erythropoietin was not correlated with any of the determined variables. In neither group erythropoietin was linked to the haematocrit or hemoglobin concentration.