Ornithine and histidine decarboxylase activities in mice sensitized to endotoxin, interleukin-1 or tumour necrosis factor by D-galactosamine.

1. An injection of D-galactosamine (GalN) into mice together with a lipopolysaccharide (LPS or endotoxin), interleukin-1 (IL-1) or tumour necrosis factor (TNF), sensitized the mice and induced fulminant hepatitis with severe congestion resulting in rapid death. Since LPS and these cytokines induce ornithine decarboxylase (ODC) and histidine decarboxylase (HDC) in the liver and spleen of mice, the effects of GalN on the induction of ODC and HDC in these organs were examined. 2. The induction of ODC by LPS, IL-1 or TNF was suppressed by GalN in the liver, and this suppression preceded the hepatic congestion. There was good agreement between the degree of hepatic congestion and the suppression of ODC induction by various amounts of GalN. The induction of ODC in the spleen was suppressed only at the highest dose of GalN examined. 3. GalN is known to deplete uridine 5'-triphosphate (UTP), resulting in the suppression of RNA and protein synthesis. An injection of uridine, the precursor of UTP, diminished the GalN-induced suppression of ODC induction by LPS and prevented the hepatic congestion and death. 4. LPS-pretreatment before injection of LPS plus GalN prevented the suppression of ODC activity and prevented the hepatic congestion and death. 5. An injection of putrescine, the product of ODC, prolonged survival time and delayed the development of hepatic congestion. However, injection of an ODC inhibitor into the mice given LPS did not produce hepatic congestion. 6. The induction of HDC in the liver by LPS, IL-1 or TNF was not suppressed by GalN and, at high doses, the response to LPS was enhanced.(ABSTRACT TRUNCATED AT 250 WORDS)