Use of Immunocytochemistry of Progesterone and Estrogen Receptors for Endometrial Dating

TLDR

Immunocytochemistry with monoclonal antibodies was used to assess progesterone and estrogen receptors in endometrial tissue from normal women, showing that the technique works equally well on samples obtained by aspiration or biopsy. Receptor staining varied markedly across the menstrual cycle, with progesterone receptor positivity rising to 75 % of glandular cells in the late follicular/early luteal phase and then disappearing in glandular cells during the mid‑late luteal phase, while estrogen receptor staining peaked in the mid‑follicular phase and also diminished later, illustrating three distinct phases of receptor expression.

Abstract

Endometrial progesterone and estrogen receptors were studied by immunocytochemistry using monoclonal antibodies during the menstrual cycle in normal women. We initially compared immunocytochemical staining of progesterone and estradiol receptors on endometrial fragments obtained by either aspiration or endometrial biopsy and found that immunocytochemistry could be performed easily on tissue obtained in either way. The immunocytochemical studies showed that the concentration and distribution of receptors changed markedly during the normal menstrual cycle. These changes were distributed in three characteristic phases. During phase I, corresponding to the midfollicular period (days 7–8), a small proportion (25%) of stromal and glandular cells stained positively for the progesterone receptor, whereas estrogen receptor staining was more intense and more frequent (50% of cells). Phase II, which included both the late follicular and early luteal periods (days 9–19), was characterized by a marked staining of progesterone receptors in the majority of glandular cells (75%) and somewhat less abundant and less frequent staining in stromal cells (50%). Estrogen receptor staining was present in about half of the glandular and stromal cells. Phase HI, the mid- and late luteal period (days 21–27), was characterized by the disappearance of estrogen and progesterone receptor staining in glandular cells, although faint staining for both receptors was found in stromal cells. These variations in progesterone receptor staining are potentially useful for determining the effect of progesterone on endometrial maturation.