Prolactin in hirsute women: possible roles for androgens in suppressing basal levels, and for oestrogens in enhancing TRH-induced responses
McKenna, T.J.; Cunningham, S.; Culliton, M.; Daly, L.; Moore, A.; Magee, F.; Smyth, P.P.
Acta Endocrinologica 106(1): 15-20
1984
ISSN/ISBN: 0001-5598 PMID: 6233834 Document Number: 227042
Hyperprolactinemic patients occasionally demonstrate hirsutism and elevated levels of dehydroepiandrosterone-sulfate, DHA-S, a weak androgen of adrenal origin. Abnormal adrenal function is frequently observed in hirsute patients. Prolactin may modulate normal adrenal secretion and derangements of adrenal androgen secretion may be due to abnormalities in prolactin. The possibility that elevated prolactin levels may be involved in the pathogenesis of hyperandrogenemia in hirsute patients was examined. However, basal prolactin levels in hirsute women, with or without menstrual disturbances, 201 .+-. 24.3 mU/l (mean .+-. SE) and 192 .+-. 24.3 mU/l, respectively, were significantly suppressed below levels in normal women, 289 .+-. 12.2 mU/l. The prolactin responses to stimulation with TRH and to suppression with L-dopa were also studied in hirsute patients. The prolactin response to TRH (maximum increment or integrated response) was exaggerated significantly in hirsute women with menstrual disturbances when compared to normal women, to hirsute women with normal menses or to normal men. This abnormal response may have been due to elevated estrone levels present in patients with oligomenorrhea (318 .+-. 49.5 pmol/l compared to 191 .+-. 12.1 pmol/l in normal women and 161 .+-. 15.5 pmol/l in hirsute women with normal menses, P < 0.05). There were no abnormalities detected in the suppression of prolactin in response to L-dopa in any of these groups. These findings do not support a role for prolactin in the pathogenesis of hyperandrogenemia in hirsute patients. Elevated androgen levels in women may bring about suppression of basal prolactin levels to values seen in normal men. Elevated estrone levels may exaggerate the stimulatory effect of TRH on prolactin secretion, as was seen in oligomenorrheic hirsute women.