Click the shadowed text below to review the important anatomic features of the pituitary gland. Normal anterior pituitary (also called the adenohypophysis) as shown by H & E staining is a mixture of acidophilic (eosinophilic), basophilic and poorly-staining cells ("chromophobes"). The acidophilic cells comprise "somatotrophs", which produce growth hormone, and "mammotrophs", which produce prolactin. The basophilic cells comprise "corticotrophs", which produce the precursor proopiomelanocortin from which ACTH, MSH, endorphins, and lipotropin are derived, "thyrotrophs", producing TSH, and "gonatotrophs", producing LH and FSH. Chromophobes comprise metabolically quiescent cells as well as "null" cells that don't secrete hormone. Hypothalamic neurons control the activity of anterior pituitary cells by secreting releasing factors into the hypophyseal portal system Anterior pituitary hormones are usually secreted in a pulsatile manner rather than continuously. This makes interpretation of measured levels of pituitary hormones challenging. Hypothalamic neurons project axons to the posterior pituitary (also called the neurohypophysis), and those axons secrete hormones directly into the circulation in the posterior pituitary.
Last modified: 1/16/97; Author: J. Harrison