IRON-AND PORPHYRIN METABOLISM IN IRON DEFICIENCY ANEMIA

Abstract

Despite the recent progress in the biochemical knowledge on porphyrin metabolism, quantitative determination of porphyrin concentration in the urine and blood had not been generally practised in a clinical medicine. However, it is of much scientific interest and of high clinical value to investigate on iron-and porphyrin metabolism in various kinds of blood disorders. In this report, data on serum iron level, unsaturated serum iron binding capacity and free red blood cell protoporphyrin level in various kinds of anemia are presented and the clinical meaning of the increased free red blood cell protoporphyrin concentration in iron deficiency anemia is discussed. The results obtained in this study are summarized as follows. 1) Depletion in serum iron level and elevation in unsaturated iron binding capacity were characterstic pattern of iron deficiency anemia. On the contrary, an unsaturated serum iron binding capacity in a case with hemochromatosis was evidently decreased. 2) An elevated free red blood cell protoporphyrin level was observed charactristically in iron deficiency anemia, and also in cases with lead poisoning. In a case with pernicious anemia, a free red blood cell protoporphyrin level was definitely decreased. 3) From the results of our experiments, it is strongly suggested that the free protoporphyrin in erythrocytes markedly increased in iron deficiency anemia might be utilized for heme synthesis, provided a suitable condition could be prepared for. 4) In cases of iron deficiency anemia, it was observed that an unsaturated serum iron binding capacity seemed to vary in good proportion to a free red blood cell protoporphyrin concentration, while a hemoglobin concentration, red blood cell count and serum iron level seemed to be variable independently to some extent. 5) Several cases were observed who still showed a high free red blood cell concentration or a high unsaturated iron binding capacity, even after a red blood cell count, hemoglobin concentration and serum iron level returned to normal as a result of iron therapy. Such cases were likely to have episodes of repeated relapses. Two such cases were illustrated. 6) A comparison of the hematological data in twelve cases of pretreated idiopathic hypochromic anemia with that in the same numbers of anemia due to blood loss revealed that the free red blood cell protoporphyrin concentration was definitely higher in the former than in the latter, while the other data not significantly differed each other.