Urocortin III is a neuropeptide hormone and member of the corticotropin-releasing factor (CRF) family which includes mammalian CRF , urocortin , urocortin II , frog sauvagine, and piscine urotensin I.

Human urocortin III shares 90, 40, 37, and 21% identity to mouse urocortin III , mouse urocortin II , human urocortin , and mouse urocortin, respectively. Urocortin III selectively binds to type 2 CRF receptors (Kis = 21.7, 13.5, and >100 nM for rat CRF2α, rat CRF2β, and human CRF1, respectively). It stimulates cAMP production in CHO cells expressing rat CRF2α and mouse CRF2β (EC50s = 0.16 and 0.12 nM, respectively) as well as cultured anterior pituitary cells expressing endogenous CRF2β. Urocortin III is co-released with insulin to potentiate glucose-stimulated somatostatin release in vitro in human pancreatic β-cells.2

In vivo, urocortin III reduces food intake in a dose- and time-dependent manner in mice with a minimum effective dose (MED) of 0.3 nmol/animal.3 It increases swimming time in a forced swim test in mice, indicating antidepressant-like activity.4