Study identifies a cellular basis for increased gut sensitivity in women via an estrogen-driven paracrine mechanism in the colon.1[2] Visceral pain disorders, such as irritable bowel syndrome, have a marked prevalence in women due to enhanced signaling between enterochromaffin (EC) cells in the intestinal mucosa and sensory nerve fibers.[1][2] Estrogen increases Olfr78 receptor expression on peptide YY (PYY)-producing L-cells, thereby increasing their sensitivity to acetate and PYY release.[1][2][3] Increased PYY acts on neighboring EC cells via the NPY1R receptor, leading to higher serotonin release and pain in the gut.[1][2] Experiments in mice have shown higher basal sensory nerve activity in females versus males, confirmed by comparing intact and ovariectomized females with estrogen supplementation.[2][3] L-cell profiling revealed 248 genes upregulated and 35 downregulated following estrogen exposure.Hormonal fluctuations, along with intrinsic (stress) or environmental (diet) factors, amplify this colonic circuitry and lead to maladaptive gut sensitivity[1][2].