Protein Malnutrition and the Febrile Response in the Fischer Rat

We assessed the effect of protein deprivation on the ability of peritoneal macrophages from Fischer rats to produce interleukin-1 (IL-i) after in vitro stimulation. Pyrogenic activity of supernatants was measured by an in vivo febrile response assay. Control rats were given a 23 % casein diet and protein-malnourished rats were given an 8 % casein diet for 4 weeks. IL-i-containing supematants prepared from peritoneal macrophages were injected into assay rats, whose temperatures were measured for 6 hours (T6). Rats injected with IL-i-containing supernatants derived from peritoneal macrophage cultures of protein-deprived rats had significantly less fever (T6 = 0.20 ± 0.09#{176}C)than rats injected with IL-i containing supernatants derived from peritoneal macrophage cultures of control rats (T6 = 0.56 ± 0.09#{176}C),P <.Oi. Protein malnutrition leads to diminished pyrogenicity of macrophage culture supernatants and may be at least partly responsible for the decreased febrile response seen In the malnourished animals. Key words: interleukin-i, fever, peritoneal macrophage, nutritio