Fig. 1.

GLP-1 secretion is stimulated by oligopeptides. GLP-1 secretion triggered by (a) 0, 1, 5 and 50 mg/ml peptone (n = 34, 7, 24 and 19, respectively); (b) Gly-Sar (n = 18), Leu-Gly-Gly (n = 6), Gly-Leu (n = 6) or Gly-Phe (n = 6) (each at 10 mmol/l); (c) 0, 0.15, 1.5, 15 and 150 mmol/l Gly-Sar (n = 27, 12, 11, 28 and 12, respectively). In all cases, mixed primary cultures from murine colon were incubated for 2 h under control conditions (standard bath solution) or in the additional presence of oligopeptides, as indicated. GLP-1 secretion in each well is expressed relative to the basal secretion (control) measured in parallel on the same day and indicated by the dashed line. Data represent the mean ± SEM. **p < 0.01, ***p < 0.001 compared with their respective controls by one-way ANOVA with post hoc Dunnett’s test