Oxyntomodulin (often abbreviated OXM) is a naturally occurring 37-amino acid peptide hormone found in the colon, produced by the oxyntic (fundic) cells of the oxyntic (fundic) mucosa.  It has been found to suppress appetite.
The mechanism of action of oxyntomodulin is not well understood. It is known to bind both the GLP-1 receptor and the glucagon receptor, but it is not known whether the effects of the hormone are mediated through these receptors or through an unidentified receptor.
Oxyntomodulin has been linked to entrainment of the liver's circadian clock.
Oxyntomodulin has been investigated as a blood-glucose regulation agent in connection with diabetes.