Total plasma porphyrins in renal disease

Thirty patients suffering from chronic kidney disease were examined for urinary, fecal and total plasma porphyrins. Twenty patients had nitrogen retention whereas the remaining ten patients displayed normal values. Urinary coproporphyrin excretion and total plasma porphyrin levels were comparatively less pronounced in patients with nitrogen retention. Such changes in porphyrin metabolism could be explained by a diminished capacity for kidney excretion. It is concluded that the total amount of porphyrins synthesized in the body is decreased as a result of nitrogen retention.