Mobilization of Stored Iron in Mammals: A Review

Abstract

From the nutritional standpoint, several aspects of the biochemistry and physiology of iron are unique. In stark contrast to most other elements, most of the iron in mammals is in the blood attached to red blood cell hemoglobin and transporting oxygen to cells for oxidative phosphorylation and other purposes. Controlled and uncontrolled blood loss thus has a major impact on iron availability. Also, in contrast to most other nutrients, iron is poorly absorbed and poorly excreted. Moreover, amounts absorbed (~1 mg/day in adults) are much less than the total iron (~20 mg/day) cycling into and out of hemoglobin, involving bone marrow erythropoiesis and reticuloendothelial cell degradation of aged red cells. In the face of uncertainties in iron bioavailability, the mammalian organism has evolved a complex system to retain and store iron not immediately in use, and to make that iron available when and where it is needed. Iron is stored innocuously in the large hollow protein, ferritin, particularly in cells of the liver, spleen and bone marrow. Our current understanding of the molecular, cellular and physiological mechanisms by which this stored iron in ferritin is mobilized and distributed—within the cell or to other organs—is the subject of this review.

Biology of ferritin in mammals: an update on iron storage, oxidative damage and neurodegeneration

“…In vivo, the major way to mobilize iron from its cellular storage is via the degradation of the ferritin cage itself (Linder 2013), as shown in cells exposed to restriction of iron availability (Truty et al 2001). The involvement of lysosomes in ferritin degradation and the concomitant iron release has been shown in different cell lines exposed to iron chelating agents (particularly deferoxamine (DFO) or overexpression of FtMt) (Kidane et al 2006;Zhang et al 2010), bacterial infection (Larson et al 2004), and ferroportin activation (Asano et al 2011).…”

Reference Interval for Iron Profile in Male and Female Athletes

“…The new iron from the pool is exported into extracellular fluid by ferroportin. Then the iron binds to transferrin and transported to bone marrow for the development of new rbc (31). Polonifi et al 2010 studied that there are twelve genes that are involved in the iron metabolism of import, storage and export in human body (32).…”

Proteínas relacionadas con el metabolismo del hierro corporal

“…La alta afinidad de la Tf por el hierro se debe a que a un pH neutro, cada lóbulo idéntico de la proteína se une al mineral a través de dos residuos de tirosina (Y), uno de histidinaLa ferritina (Ft): es una molécula esférica compuesta de 24 subunidades. El peso completo de la proteína sin hierro (apoferritina) es de 500 kDa (11,13,35). Presenta dos tipos de cadenas, una pesada (H) con 183 aa, un punto isoeléctrico áci-do, un peso molecular de 21 kDa; y una liviana (L), con 175 aa, un punto isoeléctrico básico y un peso molecular de 19 kDa (13,(35)(36)(37).…”

“…El peso completo de la proteína sin hierro (apoferritina) es de 500 kDa (11,13,35). Presenta dos tipos de cadenas, una pesada (H) con 183 aa, un punto isoeléctrico áci-do, un peso molecular de 21 kDa; y una liviana (L), con 175 aa, un punto isoeléctrico básico y un peso molecular de 19 kDa (13,(35)(36)(37). El hierro parece tener mayor afinidad por la Ft H, por lo que a la cadena tipo L se le une poco o nada de hierro.…”

“…El hierro parece tener mayor afinidad por la Ft H, por lo que a la cadena tipo L se le une poco o nada de hierro. Solo la cadena H, cuenta con actividad ferroxidasa para oxidar Fe ++ a Fe +++ permitiendo la acumulación del hierro férrico, dentro de la Ft (13,36,37).…”