Iron Metabolism and Absorption Studies in the X‐linked Anaemia of Mice

Abstract

Summary. The X‐linked anaemia of mice (gene symbol, sla) is hypochromic and microcytic, and the stainable iron stores are reduced. Chemical estimates of total body iron content and serum iron concentration show low values and the total serum iron binding capacity is elevated in anaemic mice. Rapid plasma iron clearance and increased iron utilization provide further confirmation of iron deficiency in anaemic animals. Alterations in activity of haem‐containing enzymes have been sought in the heart, liver and kidney of anaemic mice, and slightly decreased activity found only in kidney cytochrome oxidase.The blood volume of mice with X‐linked anaemia is increased in spite of decreased red cell mass, and thus the anaemia is in part due to dilution. The cause of the increased blood volume has not been elucidated, but it may be related to splenic enlargement. In contrast to iron depleted humans and experimental animals, mice with X‐linked anaemia show impaired rather than increased intestinal iron absorption, indicating that the anaemia is a consequence of iron malabsorption. The defect in iron absorption may be an isolated one, since evidence of impaired retention of orally administered radio‐iodinated triolein, radio‐zinc, radio‐copper and radio‐cobalt has not been found. It is suggested that the genetically‐determined defect in the intestinal mucosa of mice with X‐linked anaemia may be due to deficiency of either an enzyme or a carrier substance necessary for the normal transfer of iron from the intestinal mucosal cell to the plasma.