FIG. 2.

Stimulation of insulin secretion in epithelial cells. Caco-2 epithelial cells were incubated either with CFM from overnight cultures of E. coli Nissle expressing GLP-1 (G), PDX-1-CPP (P), both GLP-1 and PDX-1-CPP (GP), or a control plasmid (samples denoted “20”) or with synthesized GLP-1 (amino acids 1 to 37; samples denoted “37”) for 16 h before being challenged with glucose or glycerol. (a) Reverse transcription-PCR of Caco-2 cells incubated with CFM from the indicated cell line or protein and subsequent stimulation with either glucose (“g”) or glycerol. (b) Enzyme-linked immunosorbent assay of insulin secretion by stimulated Caco-2 cells. Error bars represent 1 standard deviation for at least three experiments. P values are from a Student t test (n = 3).