Effects of recombinant human erythropoietin on porphyrin metabolism in uremic patients on hemodialysis.

Recombinant human erythropoietin (r-HuEPO) is being successfully used for the treatment of uremic anemia. Several abnormalities of heme biosynthetic pathway have been described in patients with endstage renal failure. In this condition, the activity of erythrocyte porphobilinogen deaminase has been found to be slightly increased. If this enzyme were to be the key enzyme in erythroid heme regulation, its activity would be increased to an even greater degree during the correction of uremic anemia. To assess this hypothesis, this study followed the variations of this and other parameters of porphyrin metabolism over 12 months of erythropoietin therapy in eight patients with nephrogenic anemia who underwent hemodialysis. By the first month of therapy, an increase of the previously depressed erythrocyte activity of aminolevulinate dehydratase was already evident, in coincidence with a nonsignificant in