ADMINISTRATION OF ESCHERICHIA-COLI ENDOTOXIN TO RAT INCREASES LIVER MASS AND HEPATOCYTE VOLUME IN-VIVO

We have established, in vivo, an increase in liver mass and hepatocyte volume after a single intraperitoneal administration, to fasted rats, of Escherichia coli lipopolysaccharide (0127:B8) at 3 mg/kg. The phen omenon was time- and dose-dependent and could be prevented by treatmen t with polyclonal antiserum against tumour necrosis factor-alpha (TNF- alpha) before the endotoxin injection. Endotoxin caused an increase of 26% in the hepatic mass compared with fasted controls at 24 h. An inc rease of 27% in the hepatic water content underlay the altered hepatic mass which could not be accounted for by a change in the volume of he patic blood and/or interstitial fluid (measured in vivo), suggesting a n expansion in the hepatocellular volume. This is supported by an incr ease of 25% in the K+ content of the endotoxic livers. Morphometric st udy confirmed a 15% increase in hepatocyte volume after endotoxin admi nistration. The data are discussed in the light of possible metabolic effects of increased hepatocyte volume.