Induced metabolic sequelae of tularemia in the rat: correlation with tissue damage

Serum and liver zinc concentration, amino acid uptake by liver, seromucoid content, and alpha2-macrofetoprotein production were measured in vaccinated as well as nonimmune rats exposed to either virulent (SCHU S4) or attenuated (LVS) strains of Francisella tularensi. It appears that liver damage (pyogranulomatous lesions) must occur before there is any alteration in the above variables. The presence of bacteria in the liver is not of itself sufficient to lead to the onset of systemic, induced metabolic sequelae (IMS). The occurrence of zinc redistribution in all instances of increased serum protein synthesis may imply a necessary relationship between these two sequelae. Amino acid redistribution does not appear to be linked to serum protein synthesis. An endogenous mediator of systemic IMS can be detected in tularemic rats by injection of the serum of these animals into healthy recipients. The occurrence of zinc redistribution and increased serum protein synthesis in some groups of rats in the absence of amino acids uptake by liver, as well as the apparent differential dose responsiveness of these responses, are suggestive of a multiplicity of endogenous mediators.