Figure 3.

Medium-chain fatty acid (MCFA) decanoate (C10:0) and dodecanoate (C12:0) promotes GLP-1 secretion in STC-1 cells. (A) Expression of Gpr84 in the pancreas, small intestine (duodenum, jejunum, and ileum), cecum, colon (proximal and distal colon), and STC-1 cells (n = 3). (B) GLP-1 levels in response to MCFAs (0.01, 0.1 or 1 mM, respectively) in STC-1 cells (n = 3–4). (C) cAMP inhibition assay for MCFAs (1 mM, respectively) using GPR84-expressing HEK293 cells. Cells were cultured for 24 h and then treated with or without 10 μg/mL of doxycycline (Dox, n = 6). All data are presented as relative to the forskolin (Fsk)-induced cAMP levels. (D) Mobilization of intracellular calcium ([Ca²⁺]i) induced by MCFAs (0.1 mM, respectively) was monitored using GPR40-expressing HEK293 cells. Data are presented as Ca²⁺ intensity. Cells were cultured for 24 h and then treated with or without 10 μg/mL of Dox (n = 5–6). ^**P < 0.01 (Tukey-Kramer test). These experiments were performed using independent cultures from two biological replicates. All data are presented as the mean ± standard error of mean (SEM).