The effects of iron deficiency on estradiol-induced suppression of erythropoietin induction in rats: implications of pregnancy-related anemia

Abstract

Pregnant women often develop anemia concomitant with the increase in serum erythropoietin levels, which are actually lower than those of nonpregnant anemic women due to the possible suppressive effect of endogenous estradiol on erythropoietin induction. The anemia, derived from hemodilution, does not act as a drive for erythropoietin induction, but iron deficiency, often observed during pregnancy, might. In order to demonstrate this, we investigated the effects of iron deficiency on estradiol-induced suppression of erythropoietin induction in rats. Single doses of estradiol suppressed hypoxia-, cobalt-, and bleeding-stimulated elevation of plasma erythropoietin levels and renal erythropoietin mRNA expression. Repeated administration of estradiol at 0.1 and 1 mg/kg for 2 months induced a slight anemic trend without elevation of plasma erythropoietin. Feeding an iron-deficient diet for 2 months induced plasma erythropoietin elevation without obvious anemia, but the simultaneous repeated administration of estradiol suppressed it and reversed the iron deficiency. Plasma erythropoietin levels had distinct negative correlations with plasma iron, plasma ferritin, and iron concentrations in the organs, but not with plasma hemoglobin level. These results suggest that iron deficiency would significantly stimulate erythropoietin induction during pregnancy, although estradiol might suppress it through iron restoration. (Blood. 2005;106:67-74)

Adaptive response of the heart to long-term anemia induced by iron deficiency

“…Serum concentrations of iron, blood urea nitrogen, and creatinine were determined by the 2-nitroso-5-[N-n-propyl-N-(3-sulfopropyl)amino]phenol method, the ureaseglutamate dehydrogenase-UV method, and enzymatic assay (creatinine amidohydrolase-sarcosine oxidase-peroxidase method), respectively. Serum Epo concentration was determined by radioimmunoassay as previously described (11). Serum concentration of TNF-␣ was measured with the Bio-Plex suspension array system (Bio-Rad, Hercules, CA).…”

The Effect of Chronic Iron Losses on Liver Regeneration in Male and Female Rats

“…Iron content in liver representing the current iron store 16 , was significantly lower in group M then in group F and even then group F-w. We suppose that the females have their iron store easier mobilized for physiological requirements (gravidity, lactation, and -in our experiment for blood losses), which is demonstrated by higher turnover of the iron. The metabolism of iron in females is mostly influenced by estrogen, Horiguchi 16 proved that estradiol elevated iron storage in the liver. The lower serum iron concentration and lower liver iron store with higher serum prohepcidin concentration were after PH in M-w group only.…”

Eritrograma, metabolismo do ferro e concentração sérica de eritropoetina em fêmeas caprinas da raça Saanen nos períodos de gestação, parto e pós-parto

“…Diferentemente, em humanos a gestação induz a anemia e concomitante supressão da produção de EPO. Durante a gestação as concentrações de EPO elevam-se, mas são comparativamente menores em mulheres não gestantes com o mesmo grau de anemia (Horiguchi et al 2005).…”