Figure 4. Bitter taste agonist signaling stimulates secretion of gut peptides CCK (A) and glucagon-like peptide–1 (GLP-1) (B) from STC-1 cells is SREBP-2 responsive.

STC-1 cells were cultured in the absence or presence of sterols (12 μg/ml cholesterol and 1 μg/ml 25-hydroxycholesterol), and after 24-hour incubation, medium was removed and cultures were rinsed with HBSS. Cells were pretreated in the absence or presence of 1.25 mM EGTA (for block of calcium flux) for 2 minutes as indicated, and then PTC was added to the cultured STC-1 cells at different concentrations for 45 minutes at 37°C. Secreted levels of CCK and GLP-1 were measured in the culture media by an EIA assay. Data are mean ± SEM; n = 5 for 6 separate experiments.