Fig 1. CBS and CSE expression and activity in human urothelium.

(A) Both CBS and CSE are expressed in human urothelium as demonstrated by the western blot analysis. Loading in the gel lanes was controlled by detection of GAPDH protein. (B) Human urothelium expresses CBS and CSE mRNA as determined by quantitative RT-PCR analysis. Data were calculated as Δct and expressed as mean±SE of four separate specimens. (C) Human urothelium homogenate incubation with the vehicle (basal) or with L-cysteine (the substrate) generates detectable amount of H₂S (**p<0.01). (D) The incubation with 8-Br-cGMP significantly increases H₂S production compared to vehicle (*p<0.05). This effect is abrogated by KT5823, a selective PKG inhibitor (°p<0.05). The stimulation with d-cAMP does not affect H₂S production either in the presence or in the absence of KT5720, a selective PKA inhibitor. H₂S levels are calculated as nanomoles per milligram of protein/min and expressed as mean±SE of five different specimen.