Fig. 5. Roles of PPARγ on the regulation of P-gp and BCRP by SCFAs.

a Effects of butyrate sodium (But, 1 mM), the PPARγ agonist troglitazone (Tgz, 5 μM) and the PPARγ antagonist GW9662 (GW, 5 μM) on the protein expression of P-gp and BCRP. b Butyrate concentration-dependently induced the expression of the PPARγ protein in Caco-2 cells. c Effects of acetate (Ac), propionate (Pro) and butyrate (But) on the protein expression of the PPARγ in the intestines of SCFA-treated rats. Effects of But and Tgz on the protein expression of (d) BCRP and (e) P-gp in Caco-2 cells following PPARγ silencing. f Expression of the PPARγ protein was downregulated by PPARγ silencing with specific siRNA. Correlation analysis for protein levels of PPARγ and BCRP (g) in Caco-2 cells incubated with But or (h) in the intestines of SCFA-treated rats. Data are expressed as means ± S.D. (n = 5). *P < 0.05, **P < 0.01 vs control (Con) group; ^^P < 0.01 vs But or Tgz group; ^##P < 0.01 vs But or Tgz group in negative control silenced cells.