L. reuteri induces oxytocin secretion through release of secretin. Oxytocin measured by an ELISA released from a) induced J2-NGN3 HIOs or b) non-engineered HIOs derived from different patients for different regions of the intestine treated with bacterial medium control (LDM4), L. reuteri-conditioned medium, or 1.2 ng/ml (120 pg total) of secretin. c) oxytocin measured by an ELISA released from human mid-jejunal intestinal tissue treated with Krebs, L. reuteri-conditioned medium, or 2.5 ng/ml (12.5 ng total) of secretin. Oxytocin measured by an ELISA released from d and e) induced J2-NGN3 HIOs or f) human mid-jejunal intestinal tissue treated with Krebs, 1.0 ng/ml (100 pg total for HIO; 5 ng total for tissue) secretin 5–27, 2.5 ng/ml (250 pg total for HIO; 12.5 ng total for tissue) of secretin, and/or L. reuteri-conditioned medium. g) oxytocin or h) secretin measured by ELISA from the same induced J2-NGN3 HIOs treated with bacterial medium control (LDM4) or L. reuteri-conditioned medium. i) secretin measured by ELISA from human mid-jejunal intestinal tissue treated with bacterial medium control (LDM4) or L. reuteri-conditioned medium. Differential point shapes reflect multiple organoid batches (d, e, g, h) or unique patients (c, f, i). Significance values were determined from the least squares means derived from a linear or linear mixed model with pairwise comparisons corrected using a Benjamini-Hochberg multiple testing correction (see Supplemental Tables S2 and S3). a: n = 3 replicate monolayers per condition; b: n = 4 HIO lines with three replicate monolayers per condition; c and i: n = 3 patients with three replicate tissues per condition (9 datapoints total); d: n = 4 HIO batches with three replicate monolayers per condition (12 total datapoints); e: n = 3 HIO batches with three replicate monolayers per condition (9 total datapoints); f: n = 3 replicate tissues from one patient per condition; g and h: n = 2 HIO batches with duplicate replicate monolayers per condition, shared between the two figures.