[Determination of prolactin concentration in endometrium in the histologically normal secretory phase and in delayed transformation].

Endometrial biopsies of 92 infertile women were histologically investigated. In 46 cases the endometrium was in-phase. We found tissue prolactin by RIA examination of the endometrium on day 15 of the menstrual cycle and later. A plateau of the prolactin tissue concentration was seen between the 20th and 26th day of the cycle. A marked increase of the hormone concentration is seen at the end of the luteal phase. The endometrial prolactin tissue content was characterized by a large individual variation. A luteal phase defect was observed in 40 cases. There was a later rise of tissue prolactin concentration decreasing in contrast to the normal luteal phase at the end of the cycle. The difference was statistically significant at day 20, 26 and 28 of the menstrual cycle. Six biopsies were not included in the study. The estimation of endometrial prolactin in the late luteal phase appears to be an additional diagnostic test in case of a luteal phase-defective endometrium.