Urocortin expression in the human central nervous system

OBJECTIVE AND STUDY DESIGN Urocortin is a recently identified neuropeptide of the corticotrophin-releasing factor (CRF) family in the mammalian brain and has been demonstrated to stimulate ACTH secretion from pituitary cells, but its expression in human brain tissue including the hypothalamus has no t been examined. In this study, we first examined urocortin expression in t he hypothalamus (20 cases) and pituitary stalks (17 cases) of human brain o btained from autopsy using immunohistochemistry and mRNA in situ hybridizat ion, RESULTS Neither urocortin immunoreactivity nor mRNA hybridization signals w ere detected in the hypothalami and pituitary stalks while CRF immunoreacti vity was detected in the paraventricular nuclei of the hypothalami in 10/20 cases and in nerve fibres of the stalks in 17/17 cases, These results indi cate that urocortin does not act on the hypothalamo-pituitary-adrenal axis, at least not in the same manner as CRF in humans. We then examined urocort in expression in various portions of the brain in 7 cases, Both urocortin i mmunoreactivity and mRNA hybridization were detected in Purkinje cells of t he cerebellum and anterior horn cells of the spinal cord in specimens exami ned. Urocortin expression was, however, variably seen in superior olivary n uclei (two out of six cases examined) and in the Edingar-Westphal nuclei (o ne out of three cases examined). CONCLUSIONS The distribution of urocortin in the human central nervous syst em suggests that urocortin may work as a neurotransmitter like other neurop eptides in the human.