Anterior pituitary the secretion of thyroid-stimulating hormone (TSH). Prostaglandins are now known to inhibit adrenocorticotropic hormone (ACTH) and also to stimulate TSH, GH and LH release. GABA, through action with the hypothalamus, has been shown experimentally to influence the level of GH secretion. Clinical evidence supports the experimental findings of the excitatory and inhibitory effects GABA has on GH secretion, dependent on GABA’s site of action within the hypothalamic-pituitary unit. The homeostatic maintenance of the anterior pituitary is crucial to our physiological well being. Increased plasma levels of TSH induce hyperthermia through a mechanism involving increased metabolism and cutaneous vasodilation. Increased levels
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