Figure 1 Clostridium difficile toxin A and tumour necrosis factor (TNF)α increase corticotropin‐releasing hormone receptor 2 (CRHR2) mRNA and protein expression in HT‐29 colonic epithelial cells. (A) CRHR2 mRNA expression as measured by competitive PCR in HT‐29 cells incubated with toxin A (1 μg/ml) or TNFα (10 ng/ml) for 3 h (**p<0.001). (B) Western blot analysis for CRHR2 protein in HT‐29 cells incubated with toxin A (0.3 μg/ml) or TNFα (10 ng/ml) for 1, 3 and 8 h. (C) CRHR2 mRNA expression as measured by real‐time reverse transcription‐PCR (RT‐PCR) in HT‐29 cells incubated with toxin A (0.3 μg/ml) for 3 h following 1 h pre‐incubation with vehicle or the proteasome inhibitor MG 132 (CRHR2 mRNA expression normalised to glyceraldehyde phosphate dehydrogenase, *p<0.05).