progesterone cream
Progesterone differentially regulates the membrane-type matrix metalloproteinase-1 (MT1 -MMP) compartment of proMMP-2 activation in MG-63 cells.

Luo XH, Liao EY.

Institute of Endocrinology & Metabolism, The Second Affiliated Hospital, Hunan Medical University, Changsha, PR China. xianghangluo 21cn.com

Osteoblast-derived matrix metalloproteinases (MMPs) are considered to play a crucial role in bone formation and initiation of bone resorption by degrading the bone matrix. MMP-2 is constitutively secreted in a latent zymogen by osteoblasts, and requires the process of activation mediated by membrane-type matrix metalloproteinase-1 (MT1-MMP)/tissue inhibitor of metalloproteinase (TIMP-2) complex in the cell surface. Bone is one target tissue for progestins. In the present study, we observed the effects of progesterone on proMMP-2 activation and MT1-MMP expression, and also TIMP-2 levels in osteoblastic MG-63 cells. Gelatin zymograms and ELISA showed that progesterone have no effects on proMMP-2 activation. Using Western immunoblot analysis, we unexpectedly found that treatment with increasing doses of progesterone in MG-63 cells caused a dose-dependent increase in expression of MT1-MMP protein, and after 48h treatment, progesterone at 10(-8)M increased MT1-MMP protein level. Confocal immunohistochemistry analysis also confirmed that progesterone induced MT1-MMP expression in MG-63 cells. The results of Northern blot analysis showed that progesterone at 10(-8)M increased MT1-MMP protein levels after 48 h treatment. We also found that TIMP-2 levels were undetectable in MG-63 cells. In conclusion, progesterone increases MT1-MMP protein and mRNA levels in MG-63 cells, but has no effects on proMMP-2 activation, which is partly attributable to the undetectable levels of tissue inhibitor of metalloproteinase-2 (TIMP-2). Our studies suggest that TIMP-2 is involved in proMMP-2 activation, and regulation of MT1-MMP by progesterone may contribute to its actions on bone formation.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11507673&dopt=Abstract progesterone, progesterone cream



progesterone cream
Progesterone inhibits transcriptional activation of human chorionic gonadotropin-alpha gene through protein kinase A pathway in trophoblast cells.

Yamamoto T, Matsumoto K, Kurachi H, Okamoto Y, Nishio Y, Sakata M, Tasaka K, Murata Y.

Department of Obstetrics and Gynecology, Osaka University, Faculty of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan. yamamoto gyne.med.osaka-u.ac.jp

The purpose of this study was to analyze the mechanism of transcriptional inhibition of human chorionic gonadotropin-alpha (hCGalpha) gene by progesterone in trophoblast cells. We stably transfected -290 bp hCGalpha promoter-CAT constructs (-290halphaCAT) into Rcho-1 cells and monitored the promoter activities. Differentiation-dependent activation of -290 bp hCGalpha promoter containing a tandem repeat of cAMP response element (CRE) was inhibited by progesterone in a dose-dependent manner. To further analyze the mechanism of the progesterone action, Rcho-1 cells stably transfected with -290halphaCAT were treated with forskolin in the presence of progesterone. Progesterone inhibited forskolin-induced transcriptional activation of hCGalpha gene. Moreover, progesterone inhibited forskolin-induced transcriptional activation of CRE-CRE-tk-CAT. These results suggest that progesterone may inhibit cAMP-induced transcriptional activation of hCGalpha gene through CRE. Although progesterone did not alter the amount of CRE-binding protein (CREB), which is a main transcriptional factor bound to CRE(s) on hCGalpha promoter, progesterone abolished forskolin-induced CREB phosphorylation. In addition, pretreatment with progesterone abolished forskolin-induced activation of nuclear protein kinase A (PKA). In conclusion, progesterone inhibits hCGalpha gene transcription, at least in part, via the CRE region by inhibiting CREB phosphorylation through PKA pathway in trophoblast cells.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11514056&dopt=Abstract progesterone, progesterone cream



progesterone cream
Progesterone oxidation by cytochrome P450 2D isoforms in the brain.

Hiroi T, Kishimoto W, Chow T, Imaoka S, Igarashi T, Funae Y.

Department of Chemical Biology, Osaka City University Medical School, Osaka 545-8585, Japan. toyoko-loy med.osaka-cu.ac.jp

The existence of cytochrome P450 2D isoforms in the brain has been demonstrated, although their physiological functions remain to be elucidated. In this study we demonstrated that recombinant rat cytochrome P450 2D1 and 2D4 and human cytochrome P450 2D6 possess progesterone 6 beta- and 16 alpha- hydroxylation activities; 2 beta- and 21-hydroxylation activities; and 2 beta-, 6 beta-, 16 alpha- and 21-hydroxylation activities, respectively. Cytochrome P450 2D4 had the lowest K(m) value and the highest maximum velocity value toward these activities. Progesterone 2 beta- and 21-hydroxylation activities were also detected in rat brain microsomes, and these activities were completely inhibited by anticytochrome P450 2D antibodies. The presence of endogenous 2 beta- and 21-hydroxyprogesterones in rat brain tissues was also demonstrated. The mRNAs of cytochrome P450 2D4, CYP11A, and 3 beta-hydroxysteroid dehydrogenase were detected in the rat brain, suggesting that progesterone was generated from cholesterol by CYP11A and 3 beta-hydroxysteroid dehydrogenase and then underwent hydroxylation to hydroxyprogesterones by cytochrome P450 2D4 in rat brain. Collectively, our findings support the idea that cytochrome P450 2D may be involved in the regulation (metabolism and/or synthesis) of endogenous neuroactive steroids, such as progesterone and its derivatives, in brain tissues.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11517168&dopt=Abstract progesterone, progesterone cream



progesterone cream
[The role of progesterone in the regulation of gene expression of insulin-like growth factor-I receptor in human decidual stromal cells of early pregnancy in vitro]

[Article in Chinese]

Li S, Li L, Cao Z, Peng Z, Han Z, Yang Y.

Department of Obstetrics and Gynecology, West China Second Hospital, Sichuan University, Chengdu 610041, China.

OBJECTIVE: To assess the effect of progesterone on the gene expression of insulin-like growth factor-I receptor (IGF-I R) in human decidual stromal cells of early pregnancy in vitro. METHODS: Semiquantitative reverse transcriptase polymerase chain reaction, using beta-ACTIN as internal standard, was applied to determine the levels of IGF-I R mRNA in human decidual stromal cells of early pregnancy in vitro after cultured with different concentrations of progesterone for 72 hours or cultured with 0.1 mumol/L of progesterone for different periods of time. RESULTS: The expression of IGF-I R mRNA was significantly positive in human decidual stromal cells of early pregnancy in vitro. The levels of IGF-I R mRNA were down-regulated by progesterone, and showed significant negative-correlation with the concentration of progesterone (r = -0.680, P < 0.001). The levels of IGF-I R mRNA showed no significant correlation with time when the final concentration of progesterone was 0.1 mumol/L (r = 0.005, P > 0.05). CONCLUSION: Progesterone may play an important role in the regulation of proliferation and decidualization of stromal cells by down-regulating the expression of IGF-I R mRNA in human decidual stromal cells of early pregnancy, which is important for the maintenance of early pregnancy.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12575179&dopt=Abstract progesterone, progesterone cream



progesterone cream
Interactions between progesterone receptor isoforms in myometrial cells in human labour.

Pieber D, Allport VC, Hills F, Johnson M, Bennett PR.

Department of Obstetrics and Gynaecology, Karl-Franzens University Graz, Austria.

Progesterone acts to maintain uterine quiescence during pregnancy. In contrast to many other species, no decrease in maternal serum levels of progesterone can be observed in humans before the onset of labour. Therefore, a 'functional' progesterone withdrawal in association with labour has been proposed. In humans the progesterone receptor (PR) exists in two isoforms, PR-A and PR-B. While PR-B generally mediates the effects of progesterone upon gene transcription, the role of PR-A during pregnancy, and in parturition, is unknown. In this study, term myometrium cells cultured before the onset of labour were transiently transfected with expression vectors for either PR-A or PR-B. Only those cells expressing PR-B significantly increased expression of a progesterone-sensitive reporter when stimulated with progesterone. Co-transfection of both isoforms of PR demonstrated that PR-A is a dominant repressor of transactivation in these cells. Western blot analysis showed that PR-A is present in human myometrium samples taken only after, but not before, the onset of labour. These data suggest that increased expression of PR-A in human myometrium may contribute to 'functional' progesterone withdrawal and the initiation of human labour.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11517295&dopt=Abstract progesterone, progesterone cream



progesterone cream
Role of calpain in human sperm activated by progesterone for fertilization.

Ozaki Y, Blomgren K, Ogasawara MS, Aoki K, Furuno T, Nakanishi M, Sasaki M, Suzumori K.

Department of Obstetrics and Gynecology, Nagoya City University Medical School, Mizuho, Japan.

We evaluated the activation of mu-calpain in progesterone-activated human sperm. Semen collected from fertile donors with informed consent was liquefied and subjected to percoll gradient centrifugation. After exposure to different concentrations of progesterone, the samples were used for immunostaining, SDS-PAGE and Western blot analysis. An increase of the intracellular free calcium concentration in the sperm following the addition of progesterone was observed using fura-2 AM. Immunostaining using an antibody against active mu-calpain produced 6 distinct staining patterns: (1) the acrosome, (2) an equatorial segment, (3) the whole head, (4) the neck, (5) the neck and tail or (6) unstained sperm. After addition of progesterone, the predominant type changed from the neck type (90%) to the neck and tail type (79%). Western blot analysis using a pro-mu-calpain and a mu-calpain domain III antibody revealed autodigestion of mu-calpain, indicating activation by progesterone. Using calpain-specific inhibitors it was shown that calpain activation contributes to sperm motility as well as to the acrosome reaction. These results suggest the possibility that activation of mu-calpain in human sperm by progesterone plays an important role in fertilization.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11517938&dopt=Abstract progesterone, progesterone cream



progesterone cream
The ovarian hormones and absence epilepsy: a long-term EEG study and pharmacological effects in a genetic absence epilepsy model.

van Luijtelaar G, Budziszewska B, Jaworska-Feil L, Ellis J, Coenen A, Lason W.

Department of Physiological Psychology, NICI, University of Nijmegen, PO Box 9104, 6500 HE Nijmegen, The Netherlands. luijtelaar nici.kun.nl

In the first experiment, the relationship between the phase of the estrous cycle and the number of spontaneously occurring spike-wave discharges was investigated in WAG/Rij rats, a model for generalized absence epilepsy. The electroencephalogram (EEG) was continuously recorded for 96 h in eight rats chronically equipped with cortical EEG electrodes. A circadian pattern emerged for the number of spike-wave discharges: a nadir during the first hours of the light period, and an acrophase during the first hours of the dark period. This daily maximum was increased at proestrus day compared with the other days of the cycle, when the plasma level of progesterone is enhanced specifically at these hours of this day. This suggests that progesterone enhances spike-wave discharges. There was no difference in the first few hours of the light period in the number of spike-wave discharges between proestrus and the three other days, suggesting that estradiol has no effect on spike-wave discharges. In the second study, the effects of the systemic administration of progesterone and 17 beta-estradiol on spike-wave discharges and spontaneous behavior were investigated. It was shown that progesterone (20 and 30 mg/kg) but not estradiol (0.17-1.5 mg/kg) increased the number and total duration of spike-wave discharges. On the other hand, injection of RU 38486 (10 and 30 mg/kg), an antagonist of intracellular progesterone receptors, had no effect on spike-wave discharges and did not block the stimulatory effect of progesterone. The antagonist of 17 beta-estradiol tamoxifen (1 and 3 mg/kg) did not evoke alterations in the number or duration of spike-wave discharges. Our results indicate that progesterone aggravates spike-wave discharges, but is not mediated through intracellular receptors. Since progesterone is rapidly metabolized in the brain to the positive modulator of GABA(A) receptor allopregnanolone, which increases spike-wave discharges in WAG/Rij rats, it is possible that the epileptiformic effects of progesterone are mediated through this metabolite.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11518624&dopt=Abstract progesterone, progesterone cream