Association between serum gastrin and gastric matrix metalloproteinase (MMP)-1 transcript abundance. A: serum gastrin concentrations (left y-axis, pM) and abundance of MMP-1, MMP-3, and MMP-7 transcripts relative to GAPDH (right y-axis) in subjects on proton pump inhibitors (PPIs) (gray bars, n = 85) normalized to control (Cntrl, black bars, n = 77). B: similar data for subjects on PPIs divided into two groups on the basis of serum gastrin below (n = 27) or above (n = 58) the upper limit of the reference range (30 pM). C: similar data for those control (n = 65) and PPI-treated subjects (n = 27) in whom serum gastrin was below the upper limit of the reference range. D: MMP-1 transcript abundance relative to GAPDH expressed for each quartile of serum gastrin concentration and the mean gastrin concentration within each quartile. Data are means ± SE. *P < 0.05.