Figure 2: Distribution of mRNA for guanylin (black columns) and uroguanylin (white columns) in digestive system. Guanylin is present in all parts of gastrointestinal tract with highest expression in the distal parts of the tract. In contrast, uroguanylin is mostly present in proximal parts where it could play a role in regulating pH after emptying stomach content. PJ: proximal jejunum, DJ: distal jejunum, I: ileum, C: cecum, PC: proximal colon, DC: distal colon (modified from Whitaker et al. [18]).