Corticotroph

Corticotrophs are endocrine cells of the anterior pituitary gland, that secrete adrenocorticotropic hormone (ACTH). Corticotrophs express the pro-opiomelanocorticoid (POMC gene), which encodes a precursor hormone (POMC) from which ACTH is derived by enzymatic cleavage. ACTH secretion is regulated by two releasing factors: vasopressin and corticotropin releasing factor (CRF); these peptides are released at the median eminence from the neurosecretory nerve endings of parvocellular neuroendocine neurones, whose cell bodies are located in the paraventricular nucleus of the hypothalamus. In some species, including the horse, vasopressin secreted into the systemic circulation from the posterior pituitary gland is also an important regulator of ACTH secretion. The corticotrophs are also regulated by the negative feedback actions of glucocorticoids produced by the adrenal gland in response to the actions of ACTH.

In corticotrophs, ACTH is packaged in large membrane-bound neurosecretory vesicles; these are secreted by calcium-dependent exocytosis.