Expression of TGF-β1 axis is induced in a similar manner in the obstructed kidneys of tPA+/+ and tPA–/– mice. (a) TGF-β1 protein levels in the obstructed kidneys were determined by specific ELISAs at different timepoints in tPA+/+ and tPA–/– mice. No significant difference in TGF-β1 induction after ureteral obstruction was observed between tPA+/+ and tPA–/– mice. Data are presented as mean ± SEM (n = 5, P > 0.05). (b) Western blot demonstrates TGF-β type I receptor (TβR1) in the obstructed kidneys at day 7 after UUO. The same blot was reprobed with actin to confirm equal loading of each lane. Lanes 1–5 indicate individual animals in each group. (c) Graphic presentation of relative TGF-β type I receptor abundance normalized to actin in tPA+/+ and tPA–/– mice. Virtually identical levels of TGF-β1 receptor type I protein were found in tPA+/+ and tPA–/– mice after quantitative determination.