APA Dictionary of Psychology

any hormone secreted by neurons of the hypothalamus. Neuroendocrine cells in the hypothalamus produce the hormones oxytocin and vasopressin. The axons of these cells pass through the pituitary stalk (infundibulum) to the posterior pituitary, where they are released into the bloodstream. Other neuroendocrine cells in the hypothalamus produce either releasing hormones, which stimulate secretion of anterior pituitary hormones, or inhibiting hormones, which prevent secretion of anterior pituitary hormones. These hormones travel to the anterior pituitary through the hypothalamic–pituitary portal system.