Immunohistochemical Analysis of Human Uterine Estrogen and Progesterone Receptors Throughout the Menstrual Cycle*

TLDR

Alterations in estrogen and progesterone receptor content may drive steroid‑dependent growth and differentiation in target tissues. The study used immunohistochemistry with specific monoclonal antibodies to quantify estrogen and progesterone receptor localization and intensity in glandular epithelium, stroma, and myometrium of 33 women across the menstrual cycle, comparing the results to ligand‑binding assays. ER and PgR were nuclear and both peaked during the mid‑to‑late proliferative phase, but ER declined in the secretory phase while PgR exhibited complex, cell‑type‑specific fluctuations—diminished in glandular epithelium yet maintained in stroma and myometrium—indicating discordant patterns across uterine compartments.

Abstract

Estrogen receptors (ER) and progesterone receptors (PgR) were studied immunohistochemically using specific antireceptor monoclonal antibodies in uterine tissue samples from 33 women in various stages of the menstrual cycle. Immunohistochemical localization was quantified as to intensity of staining and tissue distribution in glandular epithelium, stroma, and myometrium, and the results were compared with those of standard ligand binding assays. In all samples ER and PgR localized within the nuclei of target cells. The maximal concentrations of ER and PgR occurred in the mid- to late proliferative phase of the menstrual cycle. ER content declined throughout the secretory phase. In contrast, PgR content underwent unexpectedly complex and dyssynchronous fluctuations during the secretory phase of the menstrual cycle. Specifically, the glandular epithelium had diminished PgR content, while the stroma and myometrium maintained a significant PgR content. PgR and perhaps ER are not concordant in different cell types within the uterus. Segregation of function through alteration of receptor content may be an important mechanism in steroiddependent growth and differentiation of target tissues