FIG. 4.

Propionate (Prop) responses are not sensitive to pertussis toxin (Ptx). A: GLP-1 secretion from primary colonic cultures treated with IBMX (100 μmol/L) with or without somatostatin (Sst) (100 nmol/L) in the absence (■) or presence (□) of 0.2 μg/mL pertussis toxin (all n = 3). B: GLP-1 secretion from primary colonic cultures triggered by propionate (1 mmol/L) in the absence and presence of pertussis toxin (0.2 μg/mL). The number of wells is indicated above the bars. Mixed primary cultures from the colon were incubated in bath solution containing reagents as indicated. GLP-1 secretion in each well is expressed relative to the basal secretion (control), measured in parallel on the same day. Data represent the means ± SEM of the number of wells indicated. Statistical significance was assessed by one-way ANOVA with a post hoc Bonferroni correction test: *P < 0.05 and ***P < 0.001.