Early Pregnancy · Miscarriage
Norwitz ER et al., 2002 · N Engl J Med
The implantation of fertilized ova and the formation of the placenta are crucial steps in reproduction. This review summarizes current information about these steps, including some of the molecular mechanisms that mediate them and how they may go awry, with consequent loss of the pregnancy.
Ovarian Hormones · Progesterone
Schust DJ et al., 1996 · Hum Reprod
Progesterone is a known immunosupressant in humans and may be important in treatment regimens for women with immunological and endocrinological reproductive failure. The molecular mechanism of progesterone-mediated immunosuppression remains controversial. We used the reverse transcriptase polymerase chain reaction (RT-PCR) technique to detect progesterone receptor RNA in human peripheral blood mononuclear cells (PBMCs). No expression could be documented in PBMCs from men or women representing various reproductive states. We also used the glucocorticoid receptor antagonist RU 43044 to address the hypothesis that progesterone exerts immunomodulatory effects via interactions with the glucocorticoid receptor. Both hydrocortisone (10(-6) and 10(-7) M) and progesterone (10(-5), 10(-6) and 10(-7) M) inhibited phytohaemagglutinin-induced lymphocyte proliferation in a dose-dependent fashion. RU 43044 (10(-5) M) significantly reversed the immunosuppressive effect od hydrocortisone but not that of progesterone. These studies indicate that human PBMCs do not express the classical progesterone receptor. Our results further suggest that progesterone does not mediate its immunomodulatory effects via interaction with the glucocorticoid receptor. Interaction with other members of the steroid and thyroid hormone receptor superfamily, local conversion to other steroid substances or non-classical receptor-mediated mechanisms may be involved.
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