IRON METABOLISM. IRON STORES IN MAN AS MEASURED BY PHLEBOTOMY 1

Abstract

Hemosiderin and ferritin represent storage iron, available for hemoglobin synthesis when need arises.Previous observations (1, 2) have indi- cated that these stores must be depleted before iron deficiency becomes manifest in the circulating red cell mass.The depletion of iron stores associ- ated with normal hematological measurements may therefore be regarded as the "preclinical " phase of iron deficiency.Interest in the pathogenesis of iron deficiency anemia has led us to further methods of evaluating iron stores.A rough estimate of iron reserves may be obtained by examination of sternal mar- row for hemosiderin (2).A more quantitative measurement may be made by determination of iron mobilized for red cell production following phlebotomy.Data obtained by the latter technique are presented to define the size of the iron storage compartment in order to determine its availability and rate of replenishment in normal adult males and in subjects with abnormalities of iron metabo- lism. METHODSVolunteers were repeatedly phlebotomized as previously described (3).A balance sheet was kept on each subject recording the amount of iron removed by phle- botomy and the weekly change in red cell mass expressed in mg. of iron.Repeated blood volumes were performed in each subject, in some individuals weekly over a period of two months.Despite the development of anemia the total blood volume showed no change thought to be sig-