progesterone cream
Progesterone blocks the estradiol-stimulated luteinizing hormone surge by disrupting activation in response to a stimulatory estradiol signal in the ewe.

Richter TA, Robinson JE, Evans NP.

Laboratory of Neuroendocrinology, The Babraham Institute, Cambridge CB2 4AT, UK.

The preovulatory surges of GnRH and LH are activated by increased concentrations of circulating estradiol, but ovulation is blocked when progesterone concentrations are elevated. Although it is has been shown that this action of progesterone is due to a central inhibition of the GnRH surge, the mechanisms that underlie the blockade of the GnRH surge are poorly understood. In this study we investigated whether progesterone can block the estradiol-dependent activation stage of the GnRH surge induction process, and thus prevent expression of the LH surge. The results demonstrated that exposure to progesterone for half or the full duration of the activation stage can prevent the stimulation of LH surges by estradiol (experiment 1), whereas exposure to progesterone midway though a period of estradiol exposure, which in itself is sufficient to activate the surge, did not block the LH surge (experiment 2). These results suggest that progesterone 1) disrupts activation of the surge induction system in response to a stimulatory estradiol signal and 2) does not compromise the ability of animals to respond to a stimulatory estradiol signal applied immediately after progesterone exposure. Because the disruptive effects of activated progesterone in response to estradiol are rapid but transient, it may be that progesterone directly interferes with the activation of estradiol-responsive neural systems to block the GnRH/LH surge.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12080007&dopt=Abstract progesterone, progesterone cream



progesterone cream
Direct inhibitory effect of progesterone on oxytocin-induced secretion of prostaglandin F(2alpha) from bovine endometrial tissue.

Bogacki M, Silvia WJ, Rekawiecki R, Kotwica J.

Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, 10-718 Olsztyn, Poland.

The effect of progesterone on oxytocin-induced secretion of prostaglandin (PG) F(2alpha) from bovine endometrial tissue explants was examined. Endometrial tissue from the late luteal phase were preincubated for 20 h in control medium. Explants were then treated for 6 h with control medium, oxytocin (10(-7) M), progesterone (10(-5) M), or both hormones. Oxytocin increased the medium concentration of 13,14-dihydro-15-keto-PGF(2alpha), whereas progesterone completely suppressed the stimulatory effect of oxytocin. In experiment 2, isolated endometrial epithelial cells were incubated with progesterone (10(-5) M), oxytocin (10(-7) M), and combinations of these hormones with or without actinomycin D (1 ng/ml). Only oxytocin stimulated secretion of PGF(2alpha), and this response was suppressed by progesterone. Oxytocin induced a rapid increase in intracellular concentrations of Ca(2+) detected within 1 min of exposure of epithelial cells from the same cows. Progesterone pretreatment diminished this response. In experiment 3, direct effects of progesterone (2 nM-20 microM) on binding of (3)H-oxytocin to the membrane preparation from epithelial cells were determined by saturation analysis. Oxytocin binding was suppressed by progesterone at every dosage tested. Progesterone is capable of suppressing the ability of oxytocin to induce endometrial secretion of PGF(2alpha). This effect appears to be mediated through a direct interference in the interaction of oxytocin with its own receptor.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12080016&dopt=Abstract progesterone, progesterone cream



progesterone cream
FSH and LH induce progesterone production and progesterone receptor synthesis in cumulus cells: a requirement for meiotic resumption in porcine oocytes.

Shimada M, Terada T.

Faculty of Applied Biological Science, Hiroshima University, Higashi-Hiroshima, Hiroshima, 739-8528, Japan.

The aim of this study was to investigate the role of progesterone in the meiotic resumption of porcine oocytes. Progesterone production and progesterone receptor (PR) immunoreactivity in cumulus cells were not detected in porcine cumulus-oocyte complexes (COC) when observations were made either just after collection from the follicles or after 28 h cultivation without LH and FSH. However, the addition of LH and FSH induced PR expression in cumulus cells, concomitant with increased progesterone production. To assess the role of progesterone in the COC, an inhibitor of progesterone production, aminoglutethimide (AGT), was administered. The addition of AGT to the medium with LH and FSH significantly suppressed progesterone production in a dose-dependent fashion. When COC were cultured with LH, FSH and 0.5 x 10(-3) mol/l AGT, almost complete inhibition of progesterone production and of germinal vesicle breakdown (GVBD) was seen. However, this inhibitory effect on GVBD was overcome by additional progesterone. Moreover, 0.5 x 10(-3) mol/l AGT also suppressed the reduction in connexin43, a gap junctional protein, in cumulus cells after 28 h cultivation, and increased the level of cyclic AMP in oocytes. These results support the hypothesis that the binding of progesterone, which was secreted by LH- and FSH-stimulated cumulus cells, to its newly synthesized receptor induces GVBD in porcine oocytes, possibly through a reduction of connexin43 in cumulus cells.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12087075&dopt=Abstract progesterone, progesterone cream



progesterone cream
Estrogen and progesterone receptor expression in patients with uterine leiomyosarcoma and correlation with different clinicopathological parameters.

Bodner K, Bodner-Adler B, Kimberger O, Czerwenka K, Leodolter S, Mayerhofer K.

Department of Obstetrics & Gynecology, University of Vienna Medical School, A-1090 Vienna, Wahringer Gurtel 18-20, Austria.

BACKGROUND: We examined the expression of estrogen and progesterone receptors in patients with uterine leiomyosarcoma (LMS) to determine their influence on prognosis (overall survival and disease-free survival) and to evaluate the association between the steroid receptor expression and various clinicopathological parameters. MATERIALS AND METHODS: Estrogen and progesterone receptor expression was investigated by immunohistochemistry from paraffin-embedded tissue in 21 patients with uterine LMS. The immunohistochemical findings were correlated with different clinicopathological parameters of the patients. RESULTS: Estrogen and progesterone receptors were expressed in 57% and 43%, respectively. The relationship between estrogen and progesterone receptor expression and clinical stage, age, vascular space involvement and recurrence of disease did not reach statistical significance (p > 0.05). Neither estrogen nor progesterone receptor expression significantly influenced overall survival and disease-free survival (p > 0.05). Early tumor stage (p = 0.0001), age at diagnosis < 50 years (p = 0.02) and the absence of vascular space involvement (p = 0.04) were prognostic factors associated with a lengthened overall survival. CONCLUSION: In conclusion, the present study observed that estrogen and progesterone receptors are frequently expressed in uterine leiomyosarcoma. However, their expression did not correlate with clinical stage, age, vascular space involvement and recurrence of disease and had no influence on overall and disease-free survival. Despite the lack of prognostic impact, further clinical studies with larger numbers of cases need to be performed to verify if estrogen and progesterone receptor-positive tumors can be treated by hormonal manipulation.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12680175&dopt=Abstract progesterone, progesterone cream



progesterone cream
[Qualitative blood flow parameters in the spiral artery and progesterone concentration in pregnancy complicated by threatened abortion]

[Article in Polish]

Persona-Sliwinska A, Brazert J, Piekarski T, Miedzianowski J, Biczysko R.

Klinika Poloznictwa i Chorob Kobiecych, Katedry Ginekologii i Poloznictwa Akademii Medycznej, Poznaniu.

OBJECTIVES: The aim of the study was to determine the values of i.e. resistance index (RI) and pulsatility index (PI) in the spiral arteries and to evaluate the maternal serum concentration of progesterone trying to find correlation between these parameters in the group of patients in early pregnancy complicated by threatened abortion. STUDY METHODS: We have analysed 30 pregnant women between 5th and 12th weeks of pregnancy with the symptoms of vaginal bleeding & lower abdominal pains diagnosed as threatened abortion. In all patients transvaginal ultrasound examination with pulse color Doppler was performed. The RI and PI values were calculated for blood flow velocity waveforms obtained from the spiral arteries. The concentration of progesterone in maternal serum was evaluated by Microparticle Enzyme Immunoassay. The correlation between analysed parameters and pregnancy duration was examined with use of linear correlation by Pearson. The correlation between Doppler and biochemical parameters were analysed with use of rang correlation method by Spearman. RESULTS: Thirty flow velocity waveforms from spiral arteries were analysed and blood flow indices were calculated. We have found statistically significant negative correlation between the values of both blood flow parameters (RI & PI) and successive weeks of pregnancy (p < 0.001) and statistically significant positive correlation between maternal serum concentration of progesterone and pregnancy duration (p < 0.05). In the tested group in 40% of patients the level of progesterone was abnormal. We have not find any correlation between serum progesterone concentration and doppler parameters in our study. CONCLUSIONS: There is observed the characteristic drop of resistance to the blood flow in the vessels of the uteroplacental circulation in the successive weeks of early pregnancy in patients with threatened abortion similar to normal early pregnancies. Lack of correlation between maternal serum concentration of progesterone and blood flow parameters indicates that other hormonal factors play major role in the regulation of the blood flow in these vessels in early pregnancy. Only the combination of Doppler blood flow analysis in spiral arteries and progesterone evaluation in the maternal serum performed in first trimester may be useful for the intensive fetal monitoring of high risk pregnancies.

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progesterone cream
Seminal plasma hormone concentration after oral application of progesterone.

Feuring M, Bertsch T, Tran BM, Rossol-Haseroth K, Losel R, Tillmann HC, Schultz A, Weigel M, Wehling M.

Institute of Clinical Pharmacology, Faculty of Clinical Medicine Mannheim, University of Heidelberg, Germany.

Previous studies have revealed beneficial in vitro effects of progesterone on sperm function. The aim of this pilot study was to prove if orally given micronized progesterone leads to elevations in progesterone and/or 17alpha-hydroxyprogesterone levels in seminal plasma, since higher seminal plasma levels of these hormones could possibly have a beneficial effect on sperm function as seen in in vitro investigations. Multiple application of micronized progesterone given over 4 days (daily dose 400 mg) to 6 healthy subjects resulted in elevated seminal plasma levels of progesterone (10.90 +/- 9.02 nmol/l vs. 1.43 +/- 0.56 nmol/l, p = 0.04) and 17alpha-hydroxyprogesterone (3.09 +/- 1.72 nmol/l vs. 1.62 +/- 1.26 nmol/l, p = 0.04) whereas no significant difference could be found in testosterone levels (34.82 +/- 13.00 vs. 30.91 +/- 8.56 nmol/l, p = 0.43). In contrast, androstendione levels in seminal plasma were reduced (2.68 1.28 nmol/l vs. 3.65 +/- 1.36 nmol/l, p = 0.01). Although micronized progesterone is rapidly metabolized, oral application resulted in pronounced elevations of progesterone and 17alpha-hydroxyprogesterone in seminal plasma. Further studies will show if oral application of micronized progesterone can induce beneficial effects on sperm function such as those seen in in vitro investigations.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11862972&dopt=Abstract progesterone, progesterone cream



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Modulatory effects of gonadotrophins and insulin-like growth factor on the secretion of inhibin A and progesterone by granulosa cells from chicken preovulatory (F1-F3) follicles.

Lovell TM, Gladwell RT, Groome NP, Knight PG.

School of Animal and Microbial Sciences, University of Reading, Whiteknights, Reading RG6 6AJ, UK.

The aim of this study was to compare the actions and interactions of gonadotrophins (LH and FSH) and an analogue of insulin-like growth factor I (LR3-IGF-I) on the secretion of inhibin A, inhibin B and progesterone by cultured chicken granulosa cells derived from the three largest (F1--F3) follicles of the preovulatory hierarchy. Treatment with LH or FSH promoted marked dose-(P < 0.0001) and time- (P < 0.0001) dependent increases in both inhibin A and progesterone secretion, with the magnitude of response (< 15-fold compared with basal) increasing over time in culture. Concentrations of inhibin B were below the detection limit in all samples. Initially, F1 cells were more LH-responsive than were F3 cells in terms of progesterone secretion (P < 0.02) but this difference between follicles decreased over time in culture. In contrast, LH-induced inhibin A secretion tended to be highest from F3 cells, although this was not significant. Cells from F3 follicles were consistently more FSH-responsive than F1 cells in terms of both progesterone (P < 0.01) and inhibin A (P < 0.02) secretion. Initially, F1 cells were more responsive to LR3-IGF-I than were F3 cells in terms of progesterone secretion (P < 0.001) but were less responsive in terms of inhibin A secretion (P < 0.001). Again, these inter-follicle differences decreased over time in culture (not significant on day 3 of treatment). Co-treatment experiments showed that LR3-IGF-I enhanced both LH- and FSH-induced secretion of inhibin A and progesterone in a time- (P < 0.001) and follicle- (P < 0.001) dependent way. Initially, F1 cells showed highest LR3-IGF-I enhancement of LH-induced inhibin A and progesterone secretion; in contrast, F3 cells showed the highest LR3- IGF-1 enhancement of FSH-induced inhibin A and progesterone secretion. These inter-follicle differences persisted over time in the case of FSH-induced hormone responses but not in the case of LH-induced responses, even though the relative degree of LR3-IGF-I enhancement increased markedly over time. Collectively, these data support a positive role for IGF-I, presumably of thecal origin, as an amplifier of gonadotrophin action on granulosa cell inhibin A and progesterone production by preovulatory chicken follicles.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11866696&dopt=Abstract progesterone, progesterone cream