Effects of progesterone receptor on proliferation of uterine leiomyoma cells.

In order to study the mechanism of the effect of progesterone receptor on the growth of primary uterine leiomyoma cells, the primary cells were extracted from uterine leiomyoma cells and identified by immunohistochemistry (IHC). Mitochondrial progesterone receptor-positive [PR-M(+)], mitochondrial progesterone receptor-negative [PR-M(-)], progesterone receptor A (PR-A) and progesterone receptor B (PR-B) were screened by Western blotting. Different concentrations of Mifepristone (MIF), a progesterone receptor antagonist, were used to interfere with PR-M(+) and PR-M(-) cell lines, respectively. Proliferation and apoptosis of PR-M(+) and PR-M(-) cell lines were detected by tetramethylazolyl blue method and flow cytometry, respectively. The expression of Caspase-3 and B-cell lymphoma 2 (Bcl-2) protein was detected by Western blotting. The results showed that the growth of PR-M(+) and PR-M(-) uterine leiomyoma cells was inhibited with the increase of MIF concentration. Furthermore, the proliferation inhibition rate and apoptosis rate were gradually increased. However, the expression of Caspase-3 protein on progesterone receptor M increased, while the expression of Bcl-2 decreased. Moreover, progesterone could induce progesterone receptor M to up-regulate apoptotic protein Caspase-3 and down-regulate anti-apoptotic protein Bcl-2, thus it could inhibit the apoptosis of primary cultured uterine leiomyoma cells and promote the proliferation of leiomyoma cells.

Progesterone use to reverse the effects of mifepristone.

OBJECTIVE: To present a series of cases demonstrating successful reversal of mifepristone effects in women who chose to reverse the medical abortion process. CASE REPORTS: Four of 6 women who took mifepristone were able to carry their pregnancies to term after receiving intramuscular progesterone 200 mg. DISCUSSION: Mifepristone has been available in the US since 2000. By 2008, approximately 25% of abortions prior to 9 weeks were accomplished with mifepristone. Some women who take mifepristone wish to reverse the medical abortion process. Progesterone competes with mifepristone for the progesterone receptor and may reverse the effects of mifepristone. A PubMed literature search from 1996 to May 2012 did not reveal any trials or case studies evaluating the efficacy of progesterone use to reverse the effects of mifepristone. CONCLUSIONS: Health care professionals should be aware of the possible use of progesterone to reverse mifepristone in women who have begun the medical abortion process by taking mifepristone and then change their minds.

Antidepressant-like effects of mineralocorticoid but not glucocorticoid antagonists in the lateral septum: interactions with the serotonergic system.

The lateral septum (LS) is a limbic brain region that receives serotonergic projections from raphe neurons and participates in the modulation of stress responses and affective states. The present study determined whether mineralocorticoid receptors (MRs) and/or glucocorticoid receptors (GRs) located in the LS interact with the serotonergic system in the regulation of depressive-like behavior of rats subjected to the forced swimming test (FST). We also studied the effect of corticosterone release induced by the FST on MR- and GR-mRNA expression in the LS. Specifically, we studied the antidepressant-like effects of spironolactone (a MR antagonist), mifepristone (a GR antagonist), and the antidepressant clomipramine (CMI) administered directly into the LS. In addition, spironolactone and CMI actions were studied in animals with serotonergic depletion induced by dl-p-chlorophenylalanine (pCPA). Finally, adrenalectomized and Sham-operated rats were subjected to the FST to determine MR- and GR-mRNA expression in the LS at different post-FST intervals. The results showed that intraseptal injection of spironolactone, but not mifepristone induced antidepressant-like actions in the FST; this effect was blocked by pCPA treatment. CMI and spironolactone increased 5-HT concentrations in the LS of rats subjected to the FST. Increases in corticosterone release, induced by the FST, correlated with a decrease in MR-mRNA expression in the LS; no correlation was found with GR-mRNA expression. In conclusion, MRs in the lateral septum, but not GRs, participate in the regulation of depressive-like behavior of animals subjected to the FST. Both serotonin and corticosterone play an important role in MR actions in the LS.

[Effects of jiantai liquid on the expression of estrogen/progesterone receptors in embryo implantation dysfunction mice endometrium].

OBJECTIVE: To explore the mechanism of Jiantai liquid on the endometrium development of embryo implantation dysfunction mice. METHOD: The model of embryo implantation dysfunction mice was induced by mifepristone and treated by Jiantai liquid. All animals were sacrificed on day 8 of pregnancy. Estradiol and progesterone concentrations in serum and endometrium tissue homogenates were measured by radioimmunoassay method, the endometial expressions of estrogen receptor (ER)and progesterone receptor (PR)assessed by immunohistochemical SP method. RESULT: There were no significantly differences in the estradiol and progesterone concentrations in serum and uterus tissue homogenates among three groups( P > 0.05). Absorbency and area rate of ER, PR in model group' s gland and stroma were higher than those in model group(P < 0.05), which was similar with the control group( P > 0.05). CONCLUSION: Jiantai liquid increase the implantation rate and improve the endometrial development by increasing the expressions of ER, PR in endometrium of embryo implantation dysfunction

[Effect of jiantai liquid on expression of estrogen and progesterone receptors in uterus of mice with embryo implantation dysfunction induced by mifepristone].

OBJECTIVE: To explore the molecular mechanism of jiantai liquid (JTL) in improving endometrial receptivity of mice with embryo implantation dysfunction (EID). METHODS: Mice model of EID induced by mifepristone were intervened with JTL (Twig of Chinese Taxillus, Red Sage root, Chinese Angelica, Milkvetch root, Chuanxiong rhizome), and sacrificed on day 8 of pregnancy. The endometrial estrogen receptor (ER) and progesterone receptor (PR) protein and their gene expressions were assessed by Western blot and semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR). RESULTS: Levels of ER and PR protein and their gene expressions in the JTL treated group were significantly higher than those in the model group respectively (all P < 0.05), and showed insignificant difference from those in the normal control group (all P > 0.05). CONCLUSION: JTL could promote the development of endometrium and improve the embryo implantation by way of regulating the levels of ER and PR protein and gene expression in mice with EID.

Receptor density dictates the behavior of a subset of steroid ligands in glucocorticoid receptor-mediated transrepression.

By co-expressing glucocorticoid receptor (GR) and transcriptional reporter systems in GR-deficient Cos-7 cells, we profiled potency and efficacy of a panel of GR ligands as a function of GR expression levels (density). Our results show that potency and efficacy for GR full agonists, such as dexamethasone, in these transrepression assays are affected by receptor density. Intriguingly, receptor density dramatically influenced the behavior of the GR antagonist RU486 or the GR agonist medroxyprogesterone acetate (MPA). At high receptor density, both MPA and RU486 behaved as full agonists in transrepression: reducing GR density, however, resulted in conversion of these ligands from full agonist to full antagonists. In contrast, varying GR density could not convert cortisol and budesonide from GR agonists to antagonists. These results have clearly demonstrated, for the first time, an effect of receptor density on the agonist and antagonist properties of RU486 and MPA in GR-mediated transrepression.

Efeito do veneno de abelha na artrite induzida por antígeno em coelhos / Effect of bee venom on antigen induced arthritis in rabbit

O efeito do veneno de abelha foi avaliado na artrite induzida por antígeno, em coelhos. O veneno de abelha foi ministrado 7 dias antes da indução da artrite, por via subcutânea, nas doses de 1,5; 3,0 e 6,0 mg/Kg/dia. O líquido sinovial foi coletado, para avaliação do número total e diferencial de células; permeabilidade vascular; determinação de prostaglandina E2 e metabólitos de óxido nítrico. A influência de glicocorticóides endógenos foi investigada com metopirona e RU 38 486, em animais que receberam veneno de abelha (1,5 mg/Kg/dia). O pré-tratamento com veneno de abelha (1,5 mg/Kg/dia) reduziu o influxo de leucócitos para a articulação inflamada, assim como os níveis de prostaglandina E2. Esse efeito não foi observado nos animais que receberam metopirona. O RU 38 486 não alterou a atividade antiinflamatória do veneno de abelha.The effect of bee venom was evaluated on antigen induced arthritis, in rabbits. Bee venom was administrated subcutaneously, 7 days before arthritis was induced, in different doses: 1,5; 3,0 and 6,0 g/Kg/day. Total and differential leucocyte migration, protein leakage, intraarticular concentration of prostaglandina E2 and nitric oxide metabolites were quantified in sinovial fluid. The influence of endogenous glucocorticoids was investigated with metyrapone and RU 38 486, in animals treated with bee venom (1,5g/Kg/day). Pre-treatment with bee venom (1,5g/Kg/day) were effective in reducing leucocyte afflux, compared with control animals. Prostaglandin E2 levels were also significantly reduced in this group. This effect was not observed in animals treated with metyrapone. The anti-inflammatory activity of bee venom was not affected by RU 38 486...

Induction of apoptosis by mifepristone and tamoxifen in human LNCaP prostate cancer cells in culture.

BACKGROUND: Published data indicate that antiprogestins and antiestrogens could inhibit prostate cancer cell growth in vitro and in vivo. The main objective of the present studies was to explore the role of bcl(2) and TGFbeta(1) for induction of apoptosis in LNCaP prostate cancer cells growing in culture as a treatment response to the antiprogestin, mifepristone, and the antiestrogen, 4-hydroxytamoxifen. METHODS: In vitro cell viability (cytotoxicity), DNA fragmentation, and changes in the expression of bcl(2) and TGFbeta(1) proteins were assessed using the sulforhodamine B protein dye-binding assay, specific ELISA, and competitive inhibition assays. RESULTS: Both steroid antagonists induced a significant time- and dose-dependent cell growth inhibition (cytotoxicity). This inhibition of viable cells was associated with a significant increase in DNA fragmentation (apoptosis), downregulation of bcl(2), and induction of TGFbeta(1) protein. Abrogation of the mifepristone- and 4-hydroxytamoxifen-induced cytotoxicity by TGFbeta(1)-neutralizing antibody and by the addition of mannose-6-phosphate confirmed the correlation between induction of active TGFbeta(1) and subsequent prostate cancer cell death. The effect of mifepristone was not significantly reduced or prevented by occupying the progesterone or glucocorticoid receptors by their corresponding high-affinity native ligands. On the contrary, the effect of a combination of mifepristone with progesterone or hydrocortisone on the increase in DNA fragmentation, bcl(2) downregulation, and induction of TGFbeta(1) protein was additive and significantly different (P < 0.05) from the effect of mifepristone monotherapy. CONCLUSIONS: Our data suggest that mifepristone and tamoxifen are effective inducers of apoptosis and may represent nonandrogen-ablation, novel therapeutic approaches to overcome a potential intrinsic apoptosis resistance of androgen-independent prostate cancer cells.

Glucocorticoids downregulate cyclooxygenase-1 gene expression and prostacyclin synthesis in fetal pulmonary artery endothelium.

Prostacyclin (prostaglandin I2 [PGI2]) is a key mediator of pulmonary vascular function during early postnatal life, and its production in the pulmonary vasculature rises markedly during that period because of increasing expression of cyclooxygenase type 1 (COX-1). The postnatal rise in COX-1 may be due to the release of inhibition by glucocorticoids, since plasma glucocorticoid levels fall after birth and glucocorticoids decrease PGI2 synthesis in certain nonpulmonary cell types. We therefore studied the direct effects of dexamethasone (DEX) on COX-1 expression in early-passage ovine fetal pulmonary-artery endothelial cells (PAECs). DEX (10(-10) to 10(-6) mol/L) caused a dose-related decrease in COX-1 mRNA expression that was evident by 24 hours, was maximal at 10(-6) mol/L (50% inhibition), and was not due to changes in mRNA stability. There was a parallel decline in COX-1 protein expression. COX-1 protein rose following DEX withdrawal, and DEX blunted the stimulatory effect of 17beta-estradiol on COX-1 expression. DEX alone (10(-8) mol/L for 48 hours) caused a 93% fall in basal PGI2 production, and bradykinin- and A23187-stimulated PGI2 were diminished 96% and 94%, respectively. Similarly, PGI2 synthesis from arachidonic acid fell 86% with DEX; all of the above effects are consistent with COX-1 downregulation. The glucocorticoid receptor (GR) antagonist mifepristone (RU-486; 10(-6) mol/L) blocked the inhibitory effect of DEX, and GR expression was evident by immunoblot analysis. These findings indicate that glucocorticoids downregulate COX-1 expression and PGI2 synthesis in fetal PAECs through the activation of PAEC GR and effects on COX-1 gene transcription. This mechanism may modulate pulmonary PGI2 production in the perinatal period, and it may also play a role in the effects of glucocorticoids on the systemic circulation at a variety of ages.

The partial agonist activity of antagonist-occupied steroid receptors is controlled by a novel hinge domain-binding coactivator L7/SPA and the corepressors N-CoR or SMRT.

Steroid receptor antagonists, such as the antiestrogen tamoxifen or the antiprogestin RU486, can have inappropriate agonist-like effects in tissues and tumors. To explain this paradox we postulated that coactivators are inadvertently brought to the promoters of DNA-bound, antagonist-occupied receptors. The human (h) progesterone receptor (PR) hinge-hormone binding domain (H-HBD) was used as bait in a two-hybrid screen of a HeLa cDNA library, in which the yeast cells were treated with RU486. We have isolated and characterized two interesting steroid receptor-interacting proteins that regulate transcription in opposite directions. The first is L7/SPA, a previously described 27-kDa protein containing a basic region leucine zipper domain, having no known nuclear function. When coexpressed with tamoxifen-occupied estrogen receptors (hER) or RU486-occupied hPR or glucocorticoid receptors (hGR), L7/SPA increases the partial agonist activity of the antagonists by 3- to 10-fold, but it has no effect on agonist-mediated transcription. The interaction of L7/SPA with hPR maps to the hinge region, and indeed, the hPR hinge region squelches L7/SPA-dependent induction of antagonist-mediated transcription. Interestingly, pure antagonists that lack partial agonist effects, such as the antiestrogen ICI164,384 or the antiprogestin ZK98299, cannot be up-regulated by L7/SPA. We also isolated, cloned, and sequenced the human homolog (hN-CoR) of the 270-kDa mouse (m) thyroid/retinoic acid receptor corepressor. Binding of hN-CoR maps to the hPR-HBD. mN-CoR, and a related human corepressor, SMRT, suppress RU486 or tamoxifen-mediated partial agonist activity by more than 90%. This suppression is completely squelched by overexpression of the hPR H-HBD. Additionally, both corepressors reverse the antagonist-dependent transcriptional up-regulation produced by L7/SPA. Our data suggest that the direction of transcription by antagonist-occupied steroid receptors can be controlled by the ratio of coactivators to corepressors recruited to the transcription complex by promoter-bound receptors. In normal tissues and in hormone-resistant breast cancers in which the agonist activity of mixed antagonists predominates, steroid receptors may be preferentially bound by coactivators. This suggests a strategy by which such partial agonist activity can be eliminated and by which candidate receptor ligands can be screened for this activity.

[Inhibition of the anti-glucocorticosteroid effect of RU486 on the growth of mouse fibroblasts in culture by the immunosuppressor kf506]]. / Inhibition par l'immunosuppresseur FK506 de l'effet antiglucocorticostéroïde du RU486 sur la croissance de fibroblastes de souris en culture.

The growth of mouse L-929 fibroblasts in culture is inhibited by dexamethasone, a synthetic glucocorticosteroid, and this effect is itself suppressed by the antiglucocorticosteroid RU486 (mifepristone). Neither RU486 nor the immunosuppressant FK506 alone influence L-929 growth, and FK506 does not modify dexamethasone action. However, FK506 suppresses the antiglucocorticosteroid activity of RU486. The implication of the "anti-antagonist" activity of FK506 in its immunosuppressant properties has still to be explained. The role of the recently cloned, FK506-binding, p59 immunophilin, which binds to the heat shock protein hsp90 which itself interacts with the glucocorticosteroid receptor, is discussed.

Unilateral ovariectomy, flutamide treatment and HCG reverse the anovulatory action of antiprogesterone RU486 in rat.

Administration of antiprogesterone RU486 (4 mg/day) from estrus through proestrus to cyclic rats blocked ovulation. Moreover, RU486 increased basal serum concentrations of LH, PRL, testosterone and estradiol, while it decreased basal serum concentration of FSH. Both unilateral ovariectomy and antiandrogen flutamide treatment, as well as an ovulatory injection of HCG in the proestrus afternoon partially reversed, the ovulatory blockade of RU486. These results indicate that both the decreased FSH concentration and the increased testosterone concentration, as well as the reduced ovulatory LH release are responsible for the anovulatory effects of RU486.

Transient inhibition of RU 486 antiglucocorticoid action by dexamethasone.

RU 486 antagonizes both progesterone and glucocorticoids at the receptor level. To study the duration of RU 486 antiglucocorticoid activity on corticotropic function and to establish the means of overcoming it with dexamethasone, plasma corticolipotropic hormones and cortisol were measured in 10 healthy male patients during the 3 days after intake, at 2200 h, of a single 400-mg dose of RU 486, alone or combined with a single dexamethasone dose (1, 2, or 4 mg) given at 2400 h. On the first day after RU 486 alone, ACTH, lipotropin, and cortisol plasma levels were significantly higher than basal values. The 1-mg dose of dexamethasone totally abolished the stimulatory effect of RU 486, and higher doses of dexamethasone (2 and 4 mg) further depressed hormone levels. During the succeeding days, antiglucocorticoid activity of RU 486 alone was still present 34 h after administration, while on the third day all hormone levels returned to normal. After the combined administration, the RU 486 effect reappeared as early as the first day with the 1-mg dose of dexamethasone, while it was delayed until the third day with the higher doses. These results showed that a single 400-mg dose of RU 486 induced a response that lasted at least 34 h. Thus, a dose-dependent competition between RU 486 and dexamethasone was demonstrated. However, the suppressive effect of dexamethasone was only transient, after which the antiglucocorticoid activity of RU 486 reappeared.