Part of “CHAPTER 17 – HYPOPITUITARISM“

If the serum concentration of a pituitary hormone is shown to be inappropriately elevated (not just appropriately increased in response to a target gland deficiency), there may be a pituitary tumor present and concomitant hyposecretion of other pituitary hormones. Patients with symptoms of the amenorrhea-galactorrhea syndrome (see Chap. 13), acromegaly (see Chap. 12), or Cushing disease (see Chap. 14 and Chap. 75) must be strongly suspected of harboring a hypersecretory pituitary tumor. The mechanism of any associated hyposecretion could be the compression of normal surrounding pituitary tissue by the tumor. However, in the case of a prolactin-secreting adenoma, concomitant hypogonadism may be caused by the hormonal effect of a high serum level of prolactin, suppressing gonadotropin production and decreasing the gonadal response to the gonadotropins.39 Almost always, first-line treatment of a prolactinoma is dopamine agonist therapy; hence, measurement of serum prolactin should be part of the preoperative evaluation.