In rats with chronic dietary iron overload, a higher amount of liver ferritin L-subunit mRNA was found mainly engaged on polysomes, whereas in control rats ferritin L-subunit mRNA molecules were largely stored in ribonucleoprotein particles. On the other hand, ferritin H-subunit mRNA was unchanged by chronic iron load and remained in the inactive cytoplasmic pool. In agreement with previous reports, in rats acutely treated with parenteral iron, only the ferritin L-subunit mRNA increased in amount, whereas both ferritin subunit mRNAs shifted to polysomes. This may indicate that, whereas in acute iron overload the hepatocyte operates a translation shift of both ferritin mRNAs to confront rapidly the abrupt entry of iron into the cell, during chronic iron overload it responds to the slow iron influx by translating a greater amount of L-subunit mRNA to synthesize isoferritins more suitable for long-term iron storage.
Translational regulation of ferritin synthesis in rat liver. Effects of chronic dietary iron overload / Cairo, G; Tacchini, L; Schiaffonati, L; Rappocciolo, E; Ventura, Ezio; Pietrangelo, Antonello. - In: BIOCHEMICAL JOURNAL. - ISSN 0264-6021. - STAMPA. - 264(3):(1989), pp. 925-928.