Hypothalamic–pituitary–thyroid axis and TSH receptor antibodies may be the reason for the observation that the relation between free T4 concentration and TSH levels deviates from a pure loglinear relation that has previously been proposed. Standard procedures cover the determination of serum levels of the following hormones: For special conditions the following assays and procedures may be required: 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
Pituitary gland referred to the pituitary gland by only using the (Ancient Greek) name ἀδήν, "gland". He described the pituitary gland as part of a series of secretory organs for the excretion of nasal mucus. Anatomist Andreas Vesalius translated ἀδήν with "glans, in quam pituita destillat", "gland in which slime ("pituita") drips". Besides this 'descriptive' name, Vesalius used "glandula pituitaria", from which the English name "pituitary gland" is ultimately derived. The expression "glandula pituitaria" is still used as official synonym beside "hypophysis" in the official Latin nomenclature "Terminologia Anatomica". In the seventeenth century the supposed function of the pituitary gland to produce