Objective  To investigate the synthesis of corticotropin releasing hormone (CRH) and urocortin (Ucn)

in rat peritoneal macrophages and the effect of LPS on their expressions.   Methods  Peritoneal macrophages were harvested from Wistar rats

and cultured in DMEM with 10% fetal bovine serum.  The total RNA and total protein were extracted from normal control cells and the cells treated by LPS for 1

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4 and 8 h. Each cell group was composed of 8 samples from different rats RT-PCR was used to observe transcriptions of CRH mRNA and Ucn mRNA. ELISA was used to observe the expression of intracelluar CRH and Ucn.   Results  CRH and Ucn mRNA existed in normal rat peritoneal macrophages and LPS up-regulated them to the peak at 4 h. CRH and Ucn peptides also existed in normal rat peritoneal macrophage and they respectively reached the peaks (0.30±0.07) ng/10

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cells at 2 h and (8.68±1.25) ng/10

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cells at 8 h after LPS treatment.   Conclusion  LPS enhancet the expressions of CRH and Ucn in cultured rat peritoneal macrophages

but Ucn peptide level is higher than CRH peptide. These results indicate the macrophages are the potential resource of CRH and Ucn in inflammatory reaction.