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Porcine spermatozoa contain more than one membrane progesterone receptor.

Losel R, Dorn-Beineke A, Falkenstein E, Wehling M, Feuring M.

Faculty for Clinical Medicine Mannheim, Institute of Clinical Pharmacology, University of Heidelberg, Theodor-Kutzer-Ufer, D-68167 Mannheim, Germany.

Progesterone has been shown to be a physiologically relevant inducer of the sperm acrosome reaction. A novel protein intrinsic to microsomal membranes, membrane progesterone receptor (mPR, now termed progesterone membrane receptor component 1, PGMRC1) that binds progesterone with high affinity has been cloned from porcine liver previously, and corresponding antibodies mitigate the progesterone induced acrosome reaction. In this study we aimed at the localization of mPR in porcine spermatozoa. Immunostaining suggested the exclusive occurrence of mPR in a hardly accessible place, possibly the inner acrosomal membrane, with digitonin dramatically increasing the number of positively stained cells. Consistent with the structure prediction for mPR, its short N-terminus (NT) but not the large C-terminal part becomes accessible from outside after digitonin treatment as evidenced by the staining pattern of antibodies directed against different regions of the protein. However, digitonin treatment solubilizes a progesterone binding activity of approximately 140 kDa molecular weight, that is different from mPR, which remains in the cell membrane as demonstrated by Western blotting. Ligand binding studies confirm the dissimilarity of mPR and the digitonin-soluble progesterone binding protein. Chemical modification studies also indicate that the digitonin-soluble progesterone binding protein has a binding site that differs from that of mPR. It is concluded that more than one progesterone receptor is present in porcine spermatozoa.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15147732&dopt=Abstract progesterone, progesterone cream



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Elevated progesterone at initiation of stimulation is associated with a lower ongoing pregnancy rate after IVF using GnRH antagonists.

Kolibianakis EM, Zikopoulos K, Smitz J, Camus M, Tournaye H, Van Steirteghem AC, Devroey P.

Centre for Reproductive Medicine, Dutch-Speaking Brussels Free University, 1090 Brussels, Belgium. stratis easynet.be

BACKGROUND: The objective of this prospective study was to assess the impact of elevated serum progesterone levels on day 2 of the cycle on pregnancy rates in patients treated by IVF using GnRH antagonists. METHODS: Ovarian stimulation was started on day 2 of the cycle if progesterone levels were normal (normal-P group, n = 390). In the presence of elevated progesterone, initiation of stimulation was postponed for 1 or 2 days (high-P group, n = 20) and was started if repeat progesterone levels returned to normal range (n = 16). Stimulation was performed with recombinant FSH (rFSH) and GnRH antagonist was always started on day 6 of stimulation. RESULTS: A significantly higher exposure to progesterone and a significantly lower exposure to estradiol was present in the high-P as compared with the normal-P group from day 1 to day 8 of stimulation. In addition, a significantly lower ongoing pregnancy rate both per started cycle (5.0% versus 31.8%; P = 0.01) and per embryo transfer (6.3% versus 36.9%; P = 0.01) was present in the high-P compared with the normal-P group, respectively. CONCLUSIONS: The presence of elevated serum progesterone on day 2 of the cycle is associated with a decreased chance of pregnancy in patients treated with rFSH and GnRH antagonists.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15155603&dopt=Abstract progesterone, progesterone cream



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Luteal function and conception in lactating cows and some factors influencing luteal function after first insemination.

Hommeida A, Nakao T, Kubota H.

Animal Science Laboratory, Graduate School for International Development and Cooperation, Hiroshima University, 1-5-1 Kagamiyama, Higashi-Hiroshima 739-8529, Japan.

The objective of this study was to investigate the types and incidence of luteal sub-function in lactating cows after artificial insemination (AI) and their relationship with pregnancy, and to clarify the relationship between luteal function and parity, body condition score (BCS), milk yield, and dietary intake. In 19 cows, milk samples were collected daily from AI to confirmation of pregnancy. Milk progesterone concentrations were determined by EIA. Based on peak progesterone concentration and the day of onset of luteal phase, 15 of 30 progesterone profiles (50%) were normal, with progesterone concentration reaching 1.0 ng/ml within 5 days after insemination and > or =2.0 ng/ml thereafter. In addition, 6 (20%) were insufficient, (progesterone concentration remained < 2.0 ng/ml), 5 (17%) were delayed (progesterone reached 1.0 ng/ml after 5 days), 2 (7%) were both delayed and insufficient, one (3%) was short (progesterone >1.0 ng/ml for only 7 days), and one (3%) remained basal. Cows with a normal profile had a higher (P < 0.05) pregnancy rate than those with an abnormal profile (87% versus 33%, respectively). The amount of progesterone secreted in milk after first AI, as indicated by progesterone area under curve (AUC), was negatively correlated with milk yield (r = -0.83, P < 0.01), dry matter intake (r = -0.81, P < 0.05), total digestible nutrients (r = -0.82, P< 0.05), and digestible crude protein (r = -0.79, P <0.05). Cows that produced more milk and consumed more dry matter had less progesterone during the luteal phase. In conclusion, abnormal luteal function was associated with reduced pregnancy rates and high milk production and increased dietary intake during breeding were associated with reduced progesterone concentrations.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15159115&dopt=Abstract progesterone, progesterone cream



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Chronic treatment with progesterone but not medroxyprogesterone acetate restores the endothelial control of vascular tone in the mesenteric artery of ovariectomized rats.

Chataigneau T, Zerr M, Chataigneau M, Hudlett F, Hirn C, Pernot F, Schini-Kerth VB.

Department of Pharmacology and Physico-Chemistry of Cellular and Molecular Interactions, College of Pharmacy, Louis Pasteur University, Illkirch, France.

OBJECTIVE: To examine whether chronic administration of the natural hormone progesterone or a synthetic progestogen, medroxyprogesterone acetate, to ovariectomized rats affects the endothelial control of arterial tone in the isolated mesenteric artery. DESIGN: Sham-operated rats received a daily subcutaneous injection of solvent (sesame oil), whereas ovariectomized rats received either sesame oil, progesterone (22 mg kg/day), or medroxyprogesterone acetate (22 mg kg/day) for 4 weeks, according to their respective group. RESULTS: Phenylephrine-induced contractions were significantly increased (about 200% at 10 microM) by N-nitro-L-arginine, a nitric oxide synthase inhibitor, in intact mesenteric arterial rings from the sham-operated but not from the ovariectomized group. The progesterone but not the medroxyprogesterone treatment restored the potentiating effect of N-nitro-L-arginine on phenylephrine-induced contraction (about 180% at 10 microM). Contractions to phenylephrine were not affected by the combination of charybdotoxin plus apamin, two inhibitors of endothelium-derived hyperpolarizing factor-mediated responses, in all groups. Acetylcholine induced endothelium-dependent relaxations, which were partially inhibited by N-nitro-L-arginine and abolished by the combination of N-nitro-L-arginine plus charybdotoxin and apamin, in all groups. Acetylcholine induced similar charybdotoxin and apamin-sensitive hyperpolarizations in intact mesenteric artery segments from all groups. CONCLUSIONS: Chronic administration of progesterone, but not medroxyprogesterone, to ovarictomized rats restores the endothelium-dependent attenuation of contractile responses to phenylephrine in mesenteric arterial rings through the endothelial formation of nitric oxide. Thus, an enhancement of the protective effect of endothelial cells on the arterial wall might contribute to the beneficial effect of certain progestogen-containing preparations during hormonal treatment.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15167304&dopt=Abstract progesterone, progesterone cream



progesterone cream
Expression of progesterone receptors in bovine corpus luteum during pregnancy.

Tamane R, Pilmane M, Jemeljanovs A, Dabuzinskiene A.

Institute of Anatomy and Anthropology, Riga Stradin's University, Dzirciema iela 16, Riga LV-1007, Latvia.

The expression of progesterone receptors and matrix ribonucleic acid in 37 corpora lutea in 1-7 month's pregnant cows was investigated. Corpora lutea were obtained from slaughtered animals. Progesterone receptors expression was confirmed using biotin-streptavidin immunohistochemistry. Matrix ribonucleic acid expression was studied using pyronin staining by Unna-Brashe method. The expression of progesterone receptors was the highest in the luteal cells of the one-month pregnancy corpus luteum. It decreased significantly (p<0.05) from the third to the fourth month of pregnancy, but there was no significant difference in the expression of progesterone receptors from the first to the second and from the second to the third month of pregnancy. Also, there was no significant difference in the expression of progesterone receptors from the fourth to the fifth month and from the fifth to the sixth month of pregnancy. The expression of matrix ribonucleic acid also decreased during pregnancy, but gradually, with no significant monthly differences. It decreased significantly (p<0.05) from the sixth to the seventh month of pregnancy only. Our study shows that both indices - progesterone receptors and matrix ribonucleic acid decrease in the steroidogenic luteal cells during pregnancy and that a strong linear correlation (r=0.88) exists between these indices.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15170416&dopt=Abstract progesterone, progesterone cream



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Progesterone upregulates GATA-1 on erythroid progenitors cells in liquid culture.

da Silva Santos Duarte A, Sales TS, Mengel JO, Costa FF, Saad ST.

Hematology and Hemotherapy Centre, State University of Campinas, Campinas, SP, Brazil.

Steroids hormones modify the hematological features of homozygous sickle cell disease, including the levels of fetal hemoglobin. We used semi-quantitative RT-PCR analysis of GATA-1, GATA-2, NF-E2, and gamma-globin mRNA levels in a two-phase liquid culture system of human adult erythroid cells in order to assay the effect of progesterone upon gene expression. The levels of expression of GATA-1 and gamma-globin mRNA were significantly increased in cells treated with progesterone compared to untreated cells (1.7- to 2.0-fold). Progesterone treatment did not produce any stimulatory effect upon GATA-2 and NF-E2 mRNA expression. Differences in the synthesis of HbF protein could not be detected by flow cytometry, although we observed a small difference in mean intensity fluorescence between cells treated and cells untreated with progesterone on days 7 and 9. Using anti-transferrin receptor and anti-glycophorin A antibodies, we verified that addition of progesterone did not cause any change in erythroid proliferation and differentiation. In conclusion, it is possible that the increased expression of gamma-globin mRNA after progesterone treatment observed in this study may be related to the increased GATA-1 mRNA expression. Interactions of the steroid receptors with the basal transcriptional machinery and with transcription factors might mediate their transcriptional effects.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12490288&dopt=Abstract progesterone, progesterone cream



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Absence seizures during pregnancy in WAG/Rij rats.

Tolmacheva EA, Chepurnov SA, Chepurnova NE, Kochetkov YA, van Luijtelaar G.

M.V. Lomonosov Moscow State University, Biological Faculty, Moscow, Russia.

Spontaneously occurring spike-wave discharges (SWDs) and serum concentrations of ovarian steroid hormones were investigated before, during and after pregnancy in WAG/Rij rats, a rat strain with genetically determined absence seizures. Eight groups of rats were included in the assays of progesterone and estradiol: rats at diestrus, at various days of pregnancy and at lactating days. The number of SWDs in cortical EEG of WAG/Rij rats was decreased from the 3rd up to the 18th day of pregnancy and subsequently increased to control level. Thereafter, a new decrease was found 2-3 days after parturition. Serum concentration of progesterone was threefold increased at the 3rd day of pregnancy, remained elevated until the 18th day of pregnancy and returned to control values before delivery. Over measured days, estradiol was significantly elevated only at the 18th day of pregnancy. Results demonstrate that physiological conditions induced by the state of pregnancy lead to suppression of occurrence of SWDs. Changes in plasma progesterone concentration correspond to the changes in number of SWDs: an increased level of progesterone during pregnancy is accompanied by a decreased number of SWDs, while a decrease in circulating progesterone before parturition is paralleled by an increase of SWDs. Of interest, the relationship between SWDs and concentration of progesterone found during pregnancy is diametrically opposite to results obtained in acute administration studies of progesterone in nonpregnant animals.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15178155&dopt=Abstract progesterone, progesterone cream