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 only, with no other associated symptoms that occur in Multiple endocrine neoplasia Type 1 or Carney complex. FIPA was first described in a limited cohort of families by group in Liège, Belgium ; later FIPA was fully characterized in a multicenter international study of 64 families. FIPA families are divided into those that are homogenous and have the same type of pituitary adenoma in all the affected family members (e.g. only acromegaly, only prolactinoma, etc) , while heterogeneous FIPA families can have different pituitary adenomas in affected family members. FIPA has two known genetic causes, mutations in the "aryl hydrocarbon