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. 2002 Feb 1;109(3):401–408. doi: 10.1172/JCI13229

Figure 2.

Figure 2

Effect of aldosterone on the expression of prostasin protein in M-1 cells. (a) Cellular distribution of prostasin protein in M-1 cells. Forty micrograms of membrane and cytosolic proteins as well as 3 ml of TCA-precipitated culture medium from M-1 cells were subjected to SDS-PAGE. Blots were probed with the antiprostasin Ab and with Ab preadsorbed with the immunizing peptide. Prostasin was detected as a 40-kDa band in the culture medium only. (b) Effect of aldosterone on the expression of prostasin protein in M-1 cells. M-1 cells were treated with 1 μM aldosterone or vehicle for 24 and 48 hours. Proteins in the culture medium were TCA precipitated and subjected to SDS-PAGE. Treatment with 1 μM aldosterone increased prostasin protein expression by 3.5-fold ± 0.6-fold (for 24 hours) and 3.3-fold ± 0.3-fold (for 48 hours) when compared with the corresponding controls. This blot is representative of five separate experiments. Aldo, aldosterone; cont, control. Values are mean ± SEM (n = 5). (c) Dose dependence of aldosterone effect on prostasin. M-1 cells were treated with increasing concentrations of aldosterone (0, 10–8, 10–7, and 10–6 M) for 24 hours. The expression level of prostasin in the culture media was determined by immunoblotting. The stimulatory effect of aldosterone on prostasin protein expression was dose dependent over the range of 0–10–6 M. This blot is representative of five separate experiments. Values are mean ± SEM (n = 5). *P < 0.001, **P < 0.02.