Endometrial prolactin in hyperprolactinemic women

Objective: To observe the behavior of endometrial prolactin in hyper‐ and normoprolactinemic women. Method: Forty women were selected due to alterations in menstrual cycle and/or galactorrhea and/or sterility. Patients were divided into two groups: Group A, 19 hyperprolactinemic women; and Group B, 21 normoprolactinemic women. Their mean age was 28.3 years. Laboratory assessments were carried out in the initial follicular phase (days 3–9), initial luteal phase (days 15–21), and late luteal phase (days 22–29) in menstruating women (samples 1, 2 and 3, respectively). In the non‐menstruating women, samples were collected on days 1, 14 and 21 after the initial appointment (samples 1, 2 and 3, respectively). LH, FSH, prolactin and estradiol were measured in sample 1, while prolactin and progesterone were measured in samples 2 and 3. All women were submitted to two biopsies of the endometrium for observing the menstrual cycle, dating, and immunohistochemical detection of endometrial prolactin. Biopsies were obtained simultaneously to samples 2 and 3. To compare the two groups, Student's t‐tests or Mann–Whitney statistics were performed. Result: Results showed that the mean percentage of endometrial prolactin were higher in the late luteal phase compared to the initial one in hyper‐ and normoprolactinemic women. Conclusion: The data allowed us to conclude that serum prolactin is not correlated to endometrial prolactin, and that the synthesis of the latter is directly correlated to the differentiation of stromal cells, that is induced by progesterone in a decidualized endometrium.