Part of “CHAPTER 17 – HYPOPITUITARISM“

Prolactin elevation may occur because of oversecretion by a pituitary adenoma that may or may not be detectable on pituitary imaging. Moreover, several medications and certain physiologic processes may increase prolactin (see Table 17-4); a slightly elevated value should be repeated (see Chap. 13).36 Rarely, serum prolactin may be elevated because of macroprolactinemia.37 In this condition, the serum contains a large-molecular-mass form of prolactin that is immunoreactive but without significant bioactivity. If the serum prolactin level is >200 ng/mL but no pituitary tumor is visible by appropriate MRI, this possibility should be considered.