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 important to many animals. For instance, in fish, it is believed to control physiological color change. In adult humans, it is just a thin layer of cells between the anterior and posterior pituitary. The intermediate lobe produces melanocyte-stimulating hormone (MSH), although this function is often (imprecisely) attributed to the anterior pituitary. The intermediate lobe is, in general, not well developed in tetrapods, and is entirely absent in birds. Pituitary gland In vertebrate anatomy, the pituitary gland, or hypophysis, is an endocrine gland about the size of a pea and weighing in humans. It is a protrusion off the bottom of