Pituitary response profile following metoclopramide administration in women with different forms of hyperprolactinemia

Abstract

Aims: To test the hypothesis that macroprolactinemia is an extra-pituitary phenomenon by showing that the pituitary production of prolactin in patients with hyperprolactinemia due to macroprolactin is comparable to that in normoprolactinemic women and different from that in women with monomeric hyperprolactinemia.

Methods: Twenty-five women were studied: eight with macroprolactin hyperprolactinemia, eight with monomeric hyperprolactinemia, and nine controls. Prolactin levels were measured before and after precipitation with polyethylene glycol at baseline and at 5, 10,15, 30, and 60 min after metoclopramide administration (10 mg i.v.) in the three groups.

Results: The response profile of total and monomeric prolactin following the administration of metoclopramide was similar in women with monomeric hyperprolactinemia and normoprolactinemia but different in women with macroprolactinemia. The areas under the curve for total and monomeric prolactin were higher in patients with macroprolactinemia than in the other two groups (p < 0·0001). The maximal concentration of monomeric prolactin was reached before that of total prolactin in macroprolactinemic patients but the differences were not significant.

Discussion: Our findings support the hypothesis that prolactin secretion is comparable in women with macroprolactinemia and in normoprolactinemic women. The dynamics of the secretion suggest that the formation of prolactin complexes is an extra-pituitary process.

Chinese abstract

目的: 本研究为了验证假说, 即巨泌乳素血症是一种与血清泌乳素分泌量正常女性在泌乳素值上具有可比性, 但不同于垂体性高单体催乳素血症的一种垂体外疾病。

方法: 本研究纳入25名女性患者, 其中8名巨泌乳素性高泌乳性血症患者, 8名高单体泌乳素血症和对照组女性9名。应用聚乙二醇沉淀法检测三组沉淀前基数与甲氧氯普胺 (10mg i.v.) 给药后第5, 10, 15, 30和60分钟时的泌乳素值变化。

结果: 甲氧氯普胺给药后, 总催乳素和单体催乳素两条反应曲线在高单体泌乳素血症组和对照组中均相似, 而在巨泌乳素血症组则存在差异。巨泌乳素血症组的该两条曲线下面积高于高单体泌乳素血症组和对照组(p < 0.0001)。单体催乳素达到最高浓度的时间早于总催乳素, 但二者无明显统计学差异。

讨论: 我们的研究支持巨泌乳素血症患者与血泌乳素分泌正常女性在泌乳素分泌方面具有可比性的假说。泌乳素分泌的动态监测表明泌乳素复合体在垂体外发生形成。

Keywords:

• Hyperprolactinemia
• macroprolactinemia
• metoclopramide

Acknowledgements

We are indebted to Anne Murray for editing the manuscript and editorial assistance.

Declaration of interest

The authors have no conflict of interest to declare.