TOPICS: Hormone, hypothalamic-pituitary axis, hypothalamus, hypophyseal portal system, anterior pituitary (adenohypophysis), posterior pituitary (neurohypophysis), syndrome of inappropriate antidiuretic hormone (SIADH), negative feedback, oxytocin, antidiuretic hormone (ADH), vasopressin, thyrotropin-releasing hormone (TRH), somatostatin, D cells, somatotropin release-inhibiting hormone (SRIF), gonadotropin-releasing hormone (GnRH), growth hormone-releasing hormone (GHRH), dopamine, prolactin-inhibiting factor (PIF), corticotropin-releasing hormone (CRH), parasympathetic, vagal stimulation