The guanylin peptide family and the proposed gastrointestinal-renal natriuretic signaling axis.

According to a proposed concept of a gastrointestinal-renal natriuretic signaling axis, natriuretic peptides are released from the intestine into the circulation in response to oral salt intake and act on the kidneys as hormones to increase sodium excretion. The peptides guanylin and uroguanylin and their precursors proguanylin and prouroguanylin, respectively, have been suggested to be the mediators of this axis. A study by Preston and co-workers, however, provides important data not supporting this putative concept.