Presence and Synthesis of Inhibin Subunits in Human Decidua*

Abstract

A growing number of studies provided the evidence that human decidua is a pregnancy-related tissue capable of hormone production and metabolism. The aim of the present study was to evaluate the possible presence of inhibin subunits in human decidua. Tissue samples were collected in pregnant women during the first (8 weeks) and second trimester (18 weeks) of gestation and at term (40 weeks). Immunohistochemical data were obtained using affinity purified polyclonal antisera raised in rabbit against porcine alpha, beta A, or beta B subunits. Levels of the respective inhibin subunits were evaluated by Northern blot analysis using cDNA probes encoding sequences corresponding to each subunit. The present results indicated that human decidua contains and synthesizes inhibin alpha, beta A, and beta B subunits. The immunohistochemical data showed that decidual cells were stained with both inhibin alpha and beta B antisera, showing a similar localization. On the other hand, cells stained with inhibin beta A antisera were sparse and followed a distribution pattern different from that of cells stained with alpha or beta B antisera. The first inhibin alpha and beta B subunit mRNAs were both expressed in first trimester of pregnancy, and those mRNA levels showed a gestational related increase. The beta A subunit mRNA was expressed at very low levels at term and could not be detected earlier during pregnancy. The present data showed that human decidua actively produces inhibin subunits with a gestational-related profile. The results suggest that decidua may be a further source of inhibin-related proteins during pregnancy and emphasize the endocrine competence of human decidua.

Amniotic fluid concentrations of dimeric inhibins, activin A and follistatin in pregnancy

“…Maternal decidual cells stained with both inhibin a and b B antisera showed a similar localisation. Cells stained with b A subunit were sparse and followed a distribution pattern different from that of cells stained with a or b B antisera (18). This study's data are consistent with other reports showing that high concentrations of inhibins (19,20) and 'total' activin A (23) are present in the amniotic fluid.…”

“…Messenger RNA for inhibin a subunit has been identified in the syncytiotrophoblast and inhibin/activin b A and b B mRNAs have been identified in both cytotrophoblast and syncytiotrophoblast in the placenta (2). Immunocytochemical staining has also shown the presence of the a subunit, b A subunit and the b B subunit protein in syncytiotrophoblast (16,17) and the decidua (18).…”

Deciduoid mesothelioma: report of 21 cases with review of the literature

“…Immunohistochemical studies can also be useful, because decidual cells express estrogen receptor and alpha inhibin, markers that are absent in mesotheliomas. [45][46][47] As some early immunohistochemical studies were unable to demonstrate keratin expression in deciduosis, 43 some investigators suggested that immunostaining for this marker could assist in distinguishing deciduoid peritoneal mesothelioma from deciduosis. 1 Subsequent studies, however, demonstrate that both human decidua and extrauterine decidual reactions can be keratin positive and, therefore, keratin immunostaining has no value in discriminating between mesotheliomas with deciduoid features and deciduosis.…”

Maternal serum inhibin A levels are a marker of a viable trophoblast in incomplete and complete miscarriage

“…During pregnancy, the human trophoblast (2,3), fetal membranes (4) and decidua (5,6) express subunit mRNAs and immunoreactive proteins. Significant amounts of both proteins are secreted into the biological fluids of pregnancy (maternal and cord serum, coelomic and amniotic fluids) (7), and the feto-placental unit is the main source of circulating inhibin A and activin A (8).…”