Neuroendocrinology is regulated by afferent synaptic inputs from other brain regions. By contrast, the hormones of the anterior pituitary gland (the adenohypophysis) are secreted from endocrine cells that, in mammals, are not directly innervated, yet the secretion of these hormones (adrenocorticotrophic hormone, luteinizing hormone, follicle-stimulating hormone, thyroid-stimulating hormone, prolactin, and growth hormone) remains under the control of the hypothalamus. The hypothalamus controls the anterior pituitary gland via "releasing factors" and "release-inhibiting factors"; these are blood-borne substances [author means via bloodstream and not by the lymphatic system nor air, nor any other modes of transport] released by hypothalamic neurons into blood vessels
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