Expression of proenkephalin (PENK) mRNA in inflammatory leukocytes during experimental peritonitis in Swiss mice.

Zymosan- or thioglycollate-induced experimental peritoneal inflammation in mice may serve as a convenient model for investigations of involvement of opioid peptides derived from exudatory leukocytes in the inflammatory processes. During peritonitis, the influx of neutrophils and monocytes/macrophages correlated with a sequential appearance of proinflammatory cytokines (IL-1 β and TNFa). After both kinds of stimulation, the expression of PENK mRNA was much higher in exudatory peritoneal leukocytes than its basal level in steady state.