Hyperprolactinemia and galactorrhea: Spontaneous versus iatrogenic hypothyroidism

Abstract

Although hyperprolactinemia and galactorrhea occur in primary hypothyroidism, factors influencing their presence are not well established. To further define these factors, the duration of illness and serum levels of PRL and TSH were investigated in a group of 50 patients with spontaneous (27 females and 7 males) and iatrogenic (16 females) primary hypothyroidism. To test the hypothesis of reduced hypothalamic dopamine content in overt long-standing primary hypothyroidism, the percent increase in serum PRL after the administration of metoclopramide, a dopamine blocker (2.5 mg, iv bolus), was studied in 13 women with spontaneous primary hypothyroidism and compared with that in 10 euthyroid women. While 88.2% of the patients with spontaneous primary hypothyroidism were hyperprolactinemic, only 31% of those with iatrogenic disease had elevated PRL levels. Women with spontaneous primary hypothyroidism had a longer duration of illness (72 ± 12 vs. 6.7 ± 1.8 months; P < 0.001) and higher seru