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 apoplexy Pituitary apoplexy Pituitary apoplexy or pituitary tumor apoplexy is bleeding into or impaired blood supply of the pituitary gland at the base of the brain. This usually occurs in the presence of a tumor of the pituitary, although in 80% of cases this has not been diagnosed previously. The most common initial symptom is a sudden headache, often associated with a rapidly worsening visual field defect or double vision caused by compression of nerves surrounding the gland. This is followed in many cases by acute symptoms caused by lack of secretion of essential hormones, predominantly adrenal insufficiency. The diagnosis is