Regulation of ENaC-Mediated Sodium Reabsorption by Peroxisome Proliferator-Activated Receptors

Figure 1

Effect of PPAR$\gamma$ antagonists on amiloride-sensitive current. (a) Time course of decreases in relative Na⁺ transport in response to PPAR$\gamma$ inhibition with GW9662 ($10\hspace{0.17em}\mu \text{M}$). ${\text{mpkCCD}}_{\text{c}14}$ cells were serum-starved overnight. PPAR$\gamma$ antagonist (circles) and vehicle (squares) were added at time 0 and current was normalized to starting level. Amiloride ($10\hspace{0.17em}\mu \text{M}$; arrow) was added to the apical membrane at the end of experiment. The numbers of experiments are 24 and 26 for GW9662 and vehicle, respectively. (b) Summary graph of ENaC current density in CHO cells expressing mENaC subunits alone or coexpressed with PPAR$\gamma$₁ in the absence and presence of pretreatment with GW9662 (1 and $10\hspace{0.17em}\mu \text{M}$). The number of experiments is shown. ${}_{}{}^{*}P<.05$, versus mENaC alone; $\mathrm{\hspace{0.17em}\hspace{0.17em}}{}_{}{}^{**}P<.05$, versus mENaC + PPAR$\gamma$₁. (c) Time course for T0070907-dependent decreases in relative Na⁺ transport across monolayers of ${\text{mpkCCD}}_{\text{c}14}$ principal cells. The numbers of experiments are 9 and 6 for control and cells treated with T0070907 ($50\hspace{0.17em}\mu \text{M}$), respectively. All other conditions are the same as in (a). Some results represented here were previously published in a different format [53].

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(b)

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