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Summary. Cell suspensions were prepared from human corpora lutea obtained during the mid-luteal phase. Progesterone production was assessed after short-term incubation of luteal cell suspensions. Luteal cells were very sensitive to hCG, the concentration required for 50% maximum response being 0·01 i.u./ml, and the response was 5 times higher than the basal production.

Oestradiol (1–100 μm) induced a significant dose-related decrease in both basal and hCG-stimulated progesterone production. The A-nor steroidal compounds anordrin and AF-45 reduced hCG-stimulated progesterone production only at the high concentration of 100 μm. The ED50 values were approximately 3 μm, 75 μm and 100 μm for oestradiol, AF-45 and anordrin respectively. Anordrin showed no significant effects on basal progesterone production. In addition, oestradiol markedly inhibited the activity of 3β-hydroxysteroid dehydrogenase in luteal cells, expressed by the conversion of pregnenolone to progesterone, but the inhibitory effects of anordrin and AF-45 were negligible or relatively low.

The effects of anordrin and AF-45 were different from those of oestradiol on progesterone production by human luteal cells in vitro, indicating that neither substance is likely to be a useful luteolytic agent in women.

Keywords: A-nor steroid; oestradiol; luteal cells; progesterone; 3β-hydroxysteroid dehydrogenase; man

Immune regulation during pregnancy is complex, and thus an optimal therapy for pregnancy complications is always a big challenge to reproductive medicine. Cyclosporin A (CsA), a potent immunosuppressant, prevents rejection of allografts by hosts, but little is known about the modulating effect of CsA on the materno-fetal relationship. Here, pregnant CBA/J females mated with DBA/2 males as an abortion-prone model were administered with CsA on day 4.5 of gestation, and the pregnant CBA/J females mated with BALB/c males were established as successful pregnancy control. It was demonstrated that administration of CsA at the window of implantation significantly up-regulated the expression of CTLA-4, while down-regulating the levels of CD80, CD86, and CD28 at the materno-fetal interface in the CBA/J×DBA/2 abortion-prone matings, and the embryo resorption rate of the abortion-prone matings reduced significantly after CsA treatment, implying that modulation of costimulatory molecule expression by CsA might contribute to preventing the fetus from maternal immune attack. In addition, treatment with CsA induced enhanced growth and reduced cell apoptosis of the murine trophoblast cells. Together, these findings indicate that CsA has a beneficial effect on the materno-fetal interface in abortion-prone matings, leading to a pregnancy outcome improvement, which might provide new therapeutics for spontaneous pregnancy wastage.

Somatic cell nuclear transfer in mammalian cloning suffers from a faulty epigenetic reprogramming, which is believed to cause developmental failures in cloned embryos. Regulating the epigenetic-modifying enzymes can rescue the chromatin of cloned embryos from aberrant epigenetic status, thereby potentially promoting cloning efficiency. In this study, we investigated the effect of two histone methyltransferase inhibitors, namely, DZNep and UNC0642, on the in vitro developmental competence of cloned pig embryos. We found that (1) treatment with 10 nM DZNep or 5 nM UNC0642 for 24 h after activation had the best promoting effect on the development of cloned embryos (blastocyst rate 10.32% vs 18.08% for DZNep, and 10.44% vs 18.14% for UNC0642); (2) 10 nM DZNep and 5 nM UNC0642 significantly decreased the levels of H3K27me3 and H3K9me2, respectively, at the 2-cell, 4-cell and blastocyst stages; (3) the apoptosis level was lower in the treatment groups than in untreated control; and (4) the transcriptional expression of epigenetic genes (EZH2, GLP, G9a, Setdb1, Setdb2, Suv39h1 and Suv39h2) was decreased and pluripotency genes (Nanog, Pou5f1, Sox2 and Bmp4) was increased in treatment groups compared with control. These results indicated that treatment with DZNep and UNC0642 improves the epigenetic reprogramming of cloned embryos, which could render beneficial effect on the embryo quality and aberrant gene expression, and finally improve the developmental competence of cloned pig embryos.