PARENT SESSION
PLATFORM SESSION 9: VASCULAR AND INTRACELLULAR SIGNALS IN CORPUS LUTEUM
Chair: Davis, John¹, ¹
Co-chair: Valdezk, Kelli¹, ¹
Grand Ballroom V
2:00 PM-4:00 PM

(212) THE HUMAN CORPUS LUTEUM: WHICH CELL TYPES HAVE PROGESTERONE RECEPTORS?

Maybin, Jacqueline¹, Duncan, William¹, ¹ Obstetrics and Gynaecology, Edinburgh, GB

ABSTRACT- We have shown that the increase of macrophages and MMPs during luteolysis is prevented by hCG during luteal 'rescue'. Neither macrophages nor the fibroblast source of MMP-2 express LH/hCG receptors. Therefore paracrine signals from steroidogenic cells must be involved. As the corpus luteum is reported to express progesterone receptors, progesterone itself is an excellent candidate molecule for these paracrine effects. This study investigated the cells in the human corpus luteum able to respond directly to progesterone by co-localising nuclear progesterone receptors with specific cell markers. Seventeen human corpora lutea from across the luteal phase and after luteal rescue with exogenous hCG were studied by double-staining immunohistochemistry for nuclear progesterone receptors and specific cell antigens. Steroidogenic cells (3-HSD +ve), both theca-lutein (17-hydroxylase +ve) and granulosa-lutein (Aromatase +ve), express progesterone receptors, as do stromal fibroblasts (vimentin +ve, fibroblast antigen +ve). Vascular endothelial cells (CD31 +ve), pericytes (-Smooth Muscle Actin +ve), macrophages (CD 68 +ve) and luminal fibroblasts (vimentin +ve, fibroblast antigen +ve) do not detectable progesterone receptors. The same pattern was seen is all corpora lutea examined. Conclusions: Progesterone receptors are present on the cells responsible for MMP synthesis, and progesterone withdrawal may have a direct role is regulating MMP expression. In addition, the corpus luteum appears to have at least two distinct types of fibroblast. As macrophages and vascular cells do not have progesterone receptors, other paracrine molecules are involved in the changes seen in these cells during the luteal phase and after luteal rescue.

KEY WORDS: Corpus Luteum, Progesterone Receptors, Immunohistochemistry