Hypothalamic–pituitary–thyroid axis Hypothalamic–pituitary–thyroid axis The hypothalamic–pituitary–thyroid axis (HPT axis for short, a.k.a. thyroid homeostasis or thyrotropic feedback control) is part of the neuroendocrine system responsible for the regulation of metabolism. As its name suggests, it depends upon the hypothalamus, the pituitary gland, and the thyroid gland. The hypothalamus senses low circulating levels of thyroid hormone (Triiodothyronine (T3) and Thyroxine (T4)) and responds by releasing thyrotropin-releasing hormone (TRH). The TRH stimulates the anterior pituitary to produce thyroid-stimulating hormone (TSH). The TSH, in turn, stimulates the thyroid to produce thyroid hormone until levels in the blood return to normal. Thyroid hormone exerts negative feedback
Pituitary adenoma the endocrine system or may cause the glands to become enlarged without forming tumors. It often affects the parathyroid glands, pancreatic islet cells, and anterior lobe of the pituitary gland. MEN1 may also cause non-endocrine tumors such as facial angiofibromas, collagenomas, lipomas, meningiomas, ependymomas, and leiomyomas. Approximately 25 percent of patients with MEN1 develop pituitary adenomas. Carney complex (CNC), also known as LAMB syndrome and NAME syndrome is an autosomal dominant condition comprising myxomas of the heart and skin, hyperpigmentation of the skin (lentiginosis), and endocrine overactivity and is distinct from Carney's triad. Approximately 7% of all cardiac myxomas are