Circulating iron levels influence the regulation of hepcidin following stimulated erythropoiesis.

The stimulation of erythrocyte formation increases the demand for iron by the bone marrow and this in turn may affect the levels of circulating diferric transferrin. As this molecule influences the production of the iron regulatory hormone hepcidin, we hypothesized that erythropoiesis-driven changes in diferric transferrin levels could contribute to the decrease in hepcidin observed following the administration of erythropoietin. To examine this, we treated mice with erythropoietin and examined diferric transferrin at various time points up to 18 hours.

Food deprivation increases hepatic hepcidin expression and can overcome the effect of Hfe deletion in male mice.

Iron-loading disorders, such as hereditary hemochromatosis, are associated with inappropriately low expression of the iron regulatory hormone, hepcidin. A recent study has demonstrated that food deprivation can increase hepcidin production in mice. We have examined this effect in more detail to determine whether the pathway(s) that are responsible might provide novel targets for pharmaceutical intervention in disorders of iron homeostasis.

Ferroportin Is Essential for Iron Absorption During Suckling, But Is Hyporesponsive to the Regulatory Hormone Hepcidin.

Background & Aims: Previous studies have suggested that iron absorption in suckling mammals is refractory to stimuli that normally would decrease absorption in adults. To better understand the regulation of iron absorption during suckling, we have characterized the relationship between hepcidin, ferroportin, and iron absorption at this crucial stage of life.

Methods: To determine whether ferroportin is involved in iron absorption during suckling, absorption was measured in intestine-specific ferroportin knockout mice.

Characterization of Putative Erythroid Regulators of Hepcidin in Mouse Models of Anemia.

Iron is crucial for many biological functions, but quantitatively the most important use of iron is in the production of hemoglobin in red blood cell precursors. The amount of iron in the plasma, and hence its availability for hemoglobin synthesis, is determined by the liver-derived iron regulatory hormone hepcidin. When the iron supply to erythroid precursors is limited, as often occurs during stimulated erythropoiesis, these cells produce signals to inhibit hepatic hepcidin production, thereby increasing the amount of iron that enters the plasma.

Hepcidin independent iron recycling in a mouse model of β-thalassaemia intermedia.

In conditions such as β-thalassaemia, stimulated erythropoiesis can reduce the expression of the iron regulatory hormone hepcidin, increasing both macrophage iron release and intestinal iron absorption and leading to iron loading. However, in certain conditions, sustained elevation of erythropoiesis can occur without an increase in body iron load. To investigate this in more detail, we made use of a novel mouse strain (RBC14), which exhibits mild β-thalassaemia intermedia with minimal iron loading.