Figure 3
From: Natural phenolic compounds potentiate hypoglycemia via inhibition of Dipeptidyl peptidase IV
The inhibition of LPS-induced ERK phosphorylation and GLP-1-induced PKA production by curcumin. The protein levels of phosphorylated ERK after (A) 10, 30, and 60 min of LPS (10, 30, and 50 ng/mL) stimulation, (B) 10 and (C) 30 min of 10 ng/mL LPS stimulation followed by various concentrations of 5, 15, and 45 μM curcumin (Cur) and 5, 15, and 45 nM sitagliptin (DPP4i) treatment, respectively. (D) AR42J cells were treated with 1 nM glucagon-like peptide-1 (GLP-1), 1 nM exendin-4 (Ex-4), and mixture with 45 μM of curcumin (Cur) for 48 h. Protein expression levels were determined by Western blot. ERK, PKA, and GAPDH were stained and exposed from the same gel which cut into appropriate length after transferring. Data are expressed as means with standard deviations (mean ± SD). *P < 0.05; **P < 0.01; ***P < 0.001 vs. LPS with one-way ANOVA.
