The role of iron in the regulation of hepatic transferrin synthesis.

The role of iron supply in the regulation of hepatic transferrin synthesis by the isolated perfused rat liver was studied using nutritional iron deficiency as the experimental model. The increased transferrin release encountered in iron deficiency could be equated with enhanced de novo synthesis as evidenced by the inhibitory effects of cycloheximide and measurements of intrahepatic protein pools before and after perfusion. Refeeding with iron, sufficient to restore plasma iron and hepatic ferritin iron but before correction of anaemia, promoted a reduction towards normal in the transferrin synthetic rate. This effect was not produced by transfusional correction of the anaemia, suggesting a specific response to iron supply. Phenobarbitone treatment, which produced a marked fall in hepatic ferritin iron concentration but no change in haemoglobin or plasma iron concentrations, promoted a specific enhancement of transferrin synthesis in both control and iron deficient livers. The concentration of liver iron stores appears to be a major regulatory factor in the control of hepatic transferrin synthesis.