Effects of endotoxin on iron uptake by the hepatocyte

B. J. Potter, B. Blades, T. A. McHugh, R. M. Nunes, O. Beloqui, P. A. Slott, J. H. Rand

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12 Scopus citations

Abstract

Administration of endotoxins is often followed within 12-24 h by marked hypoferremia. Because the hepatocyte is the major site of both iron storage and transferrin synthesis, we have investigated the effects of an Escherichia coli endotoxin (lipopolysaccharide, LPS) on these parameters on isolated hepatocytes from normal Wistar rats (ND), rats previously treated intraperitoneally with 2.5 mg/kg (LD) or 25 mg/kg (HD) LPS, and control rats injected intraperitoneally with sterile saline (CD). No effects were observed on iron uptake from transferrin by ND cells incubated in vitro with up to 350 μg LPS/107 hepatocytes. There was also no significant difference in iron uptake between CD, HD, and LD hepatocytes 1 h after LPS injection. However, hepatocytes isolated 24 h after LPS administration took up iron significantly faster than controls. The uptake of non-transferrin-bound iron was also increased in HD and LD hepatocytes at 24 h but only in HD cells at 1 h. Transferrin binding was not altered in LPS-treated cells from ND rats but was depressed in cells from LPS-treated rats both at 1 h and at 24 h after injection. Transferrin receptor recycling was significantly increased at 24 h in cells from both LD and HD rats. Transferrin and total protein synthesis were also depressed at 1 h in LPS-treated rats, returning to normal values at 24 h. Direct preincubation of ND cells, however, failed to increase synthesis except at the highest concentrations of LPS. We conclude that LPS has an immediate (although indirect) effect on protein synthesis by the hepatocyte but not on iron uptake. The increase in iron uptake by the hepatocytes from LPS-treated rats corresponds in time to the decrease in serum iron seen in vivo, suggesting that the liver parenchymal cells also contribute to the observed hypoferremia resulting from LPS administration.

Original languageEnglish
Pages (from-to)20/4
JournalAmerican Journal of Physiology - Gastrointestinal and Liver Physiology
Volume257
Issue number4
StatePublished - 1989

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