In the past ten years, hyperprolactinemia has been implicated as a possible cause of several common medical problems. One of the first recognized was the so-called amenorrhea-galactorrhea syndrome. Subsequently it was learned that not all patients with elevated prolactin levels have galactorrhea1 (only about 20% of hyperprolactinemic women and even fewer men lactate), so that the absence of galactorrhea does not rule out an elevated prolactin level. Several studies have now shown that 15% to 30% of women with secondary amenorrhea (without galactorrhea) also have hyperprolactinemia.2,3 Most recently, prolactin has been implicated as a cause of impotence and/or oligospermia in men.4 It also seems likely that many pituitary tumors that in the past were thought to be nonfunctioning chromophobe adenomas were actually prolactin-producing. Thus, the number of clinical presentations associated with hyperprolactinemia and the number of patients affected are much greater than were originally estimated.
Moore TJ. ProlactinomasOur Raised Consciousness. Arch Intern Med. 1979;139(11):1223–1224. doi:10.1001/archinte.1979.03630480013008