Résumé : The presence of cholecystokinin and gastrin has been reported in the hypothalamohypophyseal system. These peptides present a peculiar distribution in the hypothalamic nuclei, the median eminence, and the neurohypophysis. CCK and gastrin have close relationships with other peptides like oxytocin, CRF, vasopressin, and the enkephalins; these relationships vary in different projecting areas and in different types of hypothalamic neurons. The functional role of G-CCK in neurosecretion seems to be linked to the role of these closely associated peptides and certainly deserves further investigation.