Comparison of the effects of aging and chronic iron loading on hepatic iron regulatory proteins. A: representative immunoblots of liver samples from young (6 mo) and old (24 mo) rats probed for TFR1, DMT1, and Fpn. Ponceau-stained membranes (Pon) are the bottom blot. B: representative immunoblots from control, and chronically iron-loaded rats (8 mo) probed for TFR1, DMT1, and Fpn. Ponceau-stained membranes (Pon) are the bottom blot. C: Quantitation of band densities shown in panel A. Results were normalized to the density of the Ponceau stain and further normalized to the young group. Results are representative of 7-9 young and old rats. Results are expressed as means + SEM. * Significant (p<0.05) effect of aging. D: Quantitation of band densities shown in panel B. Results were normalized to the density of the Ponceau stain and further normalized to the control group. Results are representative of five control and five chronically iron-loaded rats. Results are expressed as means + SEM. # Significant effect of iron-administration.