QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Schroeder, S. E. Articles by Schalinske, K. L. Search for Related Content PubMed PubMed Citation Articles by Schroeder, S. E. Articles by Schalinske, K. L.

---

Nutrient Physiology, Metabolism, and Nutrient-Nutrient Interactions

Retinoic Acid Modulates Hepatic Iron Homeostasis in Rats by Attenuating the RNA-Binding Activity of Iron Regulatory Proteins^1,2

Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011

^* To whom correspondence should be addressed. E-mail: kschalin{at}iastate.edu.

Vitamin A deficiency has been widely associated with perturbations of iron homeostasis, a consequence that can be reversed by retinoid supplementation. Despite the numerous studies that demonstrate an interaction between these 2 nutrients, the mechanistic basis for this relation has not been well characterized. Because iron regulatory proteins (IRP) have been established as central regulators of iron homeostasis, we investigated the potential role of IRP in the regulation of iron homeostasis under conditions of vitamin A deficiency and supplementation with all-trans-retinoic acid (atRA). Rats were fed a control diet or a diet deficient in either vitamin A or iron or both micronutrients. Four parallel groups of rats were supplemented with atRA daily (30 µmol/kg body weight) during the final week of this study. As expected, iron-deficient (–Fe) rats exhibited a decrease in hepatic nonheme iron levels and a subsequent increase in IRP RNA-binding activity, resulting in diminished ferritin abundance. Interestingly, atRA supplementation inhibited the increase in IRP RNA-binding activity in –Fe rats to a level that was not significantly (P = 0.139) different from control values, and it partially restored ferritin abundance. This inhibition of IRP RNA-binding activity by atRA supplementation was also associated with a 40% reduction in transferrin receptor abundance. Taken together, these results indicate that IRP represent a mechanistic link between vitamin A and the regulation of iron homeostasis, a key finding toward further understanding this important nutrient-nutrient interaction.