Neuroendocrinology its product?" and "how is information encoded in electrical activity?"[It appears that this is a primary source observation.] The pituitary gland is divided into two sections: the anterior pituitary and the posterior pituitary. The hypothalamus controls the anterior pituitary's hormone secretion by sending trophic hormones down the hypothalamohypophysial portal system. For example, thyrotropin-releasing hormone stimulates the secretion of thyroid-stimulating hormone by the anterior pituitary. The posterior pituitary is innervated by the hypothalamus; the hormones oxytocin and vasopressin are synthesized by neuroendocrine cells in the hypothalamus and stored at the nerves' ends in the posterior pituitary. They are secreted directly into
Hypothalamic–pituitary–thyroid axis these animals. The pituitary gland secretes thyrotropin (TSH; Thyroid Stimulating Hormone) that stimulates the thyroid to secrete thyroxine (T4) and, to a lesser degree, triiodothyronine (T3). The major portion of T3, however, is produced in peripheral organs, e.g. liver, adipose tissue, glia and skeletal muscle by deiodination from circulating T4. Deiodination is controlled by numerous hormones and nerval signals including TSH, vasopressin and catecholamines. Both peripheral thyroid hormones (iodothyronines) inhibit thyrotropin secretion from the pituitary (negative feedback). Consequently, equilibrium concentrations for all hormones are attained. TSH secretion is also controlled by thyrotropin releasing hormone (thyroliberin, TRH), whose secretion itself is