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Akio Miyamoto - One of the best experts on this subject based on the ideXlab platform.
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local interaction of prostaglandin f2α with endothelin 1 and tumor necrosis factor α on the Release of Progesterone and oxytocin in ovine corpora lutea in vivo a possible implication for a luteolytic cascade
Reproduction, 2004Co-Authors: Masayuki Ohtani, S Takase, M P B Wijayagunawardane, M Tetsuka, Akio MiyamotoAbstract:Endothelin-1 (ET-1) and tumor necrosis factor-a (TNFa) participate in the cascade of luteolysis. Thus, in the present study the interactions of ET-1 and TNFa with prostaglandin F 2α (PGF 2α ) on the Release of Progesterone and oxytocin (OT) within the corpus luteum (CL) were investigated. A microdialysis system (MDS) was surgically implanted in ovine CL (one MDS line/CL; 5-10 lines/ewe) formed after super-ovulation. A 4-h perfusion with PGF 2α (0.01-1 μmol l -1 ) induced no clear effect on Progesterone Release, but acutely stimulated OT Release in a dose-dependent manner. A perfusion of PGF 2α (1 μmol l -1 ) increased ET-1 Release over a period of 12 h. Two perfusions of ET-1 (0.1 μmol l -1 ) or a perfusion of ET-1 followed by TNFa (200 ng ml -1 ) decreased Progesterone Release (56-64% at 36-48 h). When the CL were pre-perfused with PGF 2α (1 μmol l -1 ), two consecutive perfusions of ET-1 decreased Progesterone Release more rapidly. Similarly, a pre-perfusion with PGF 2α followed by consecutive perfusions of ET-1 and then TNFa rapidly decreased Progesterone Release, with the inhibition most pronounced (35%) at 36-48 h. The simultaneous infusion of ET-1 with PGF 2α induced a rapid decrease in Progesterone Release (36% at 36-48 h). In a further study, the possible second messenger systems involved in PGF 2α action on the Release of Progesterone, OT and ET-1 were investigated. A perfusion with 12-Otetradecanoyl-phorbol-13-acetate (TPA; 10 μmol l -1 ), A23187 (10 μmol l -1 ), or PGF 2α + A23187 increased Progesterone Release during infusion, but decreased it after perfusion. All treatments induced a massive Release of OT during infusion, and increased ET-1 Release after infusion. These results show that ET-1 is capable of suppressing Progesterone Release in the PGF 2α -primed ovine CL in vivo and thus ET-1 works as a local luteolysin together with PGF 2α during the process of functional luteolysis. During structural luteolysis, TNFa may interact with PGF 2α and ET-1 to cause a rapid drop in Progesterone Release and accelerate the process of luteolysis. This result supports the contention that ET-1 and TNFa interact with PGF 2α as local luteolytic mediators in the ewe as previously suggested.
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oxytocin stimulates Progesterone Release from microdialyzed bovine corpus luteum in vitro
Biology of Reproduction, 1991Co-Authors: Akio Miyamoto, D SchamsAbstract:A microdialysis system (MDS) was implanted in corpora lutea (CL) from cows (Days 5-7, 8-12, and 15-18 of the estrous cycle); the CL were maintained in organ culture chambers. With this system, active substances can be applied, and a collection of steroids Released from luteal cells surrounding the microcapillary (cut-off point = 100 kDa) is possible, while luteal cells maintain cell-to-cell contact. Spontaneous pulses of Progesterone Release were observed in 90% of control (perfused with Ringer’s solution only) at 60-80-mm intervals. The infusion of bovine LH (bLH) for 20 mm (0.1-10 �ag/ml) stimulated dose-dependent Release of Progesterone. Both results indicate that the CL maintains the activity of Progesterone Release and the ability to respond to Ut stimulation in this system. Oxytocin (1-100 �M) also stimulated Progesterone Release in a dose-dependent manner. Preexposure with oxytocin antagonist blocked the stimulatory effect of oxytocin (p < 0.01) but not of LH (� < 0.05), confirming the specificity of the effect. When CL were prestimulated with a low dose of oxytocin (1 �M, 20 min) twice before bLH application, the Release of Progesterone by bLH (1 �g/m1, 20 min) was more pronounced (p < 0.05). A long-term infusion (3 h) with oxytocin and/or bLH stimulated the Release of Progesterone for the whole period of time. Oxytocin was most stimulative during the early luteal phase (Days 5-7) and decreased continuously from Days 8-12 to Days 15-18. The acute stimulatory effect on Progesterone Release by oxytocin described here has not been reported in studies using dispersed luteal cell incubations. Therefore, the overall results of this study suggest that cell-to-cell contact is important for the luteal response to oxytocin and support the hypothesis that ovarian oxytocin is involved in mechanisms of Progesterone secretion as an autocrine/paracrine factor, especially during the early luteal phase.
Samir Bhattacharya - One of the best experts on this subject based on the ideXlab platform.
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thyroid hormone stimulates Progesterone Release from human luteal cells by generating a proteinaceous factor
Journal of Endocrinology, 1998Co-Authors: M Datta, P Roy, J Banerjee, Samir BhattacharyaAbstract:Blood samples collected from 29 women (aged between 19 and 35 years) during the luteal phase of the menstrual cycle (between days 18 and 23 of the cycle) showed that deficiency in thyroid hormone level is related to a decrease in Progesterone (P 4 ) secretion. To observe the eVect of thyroid hormone on human ovarian luteal cells, 3,5,3*-triiodothyronine (T 3 ; 125 ng/ml) was added to luteal cells in vitro .T 3 significantly stimulated Progesterone Release (P<0·01) from luteal cells and this could be blocked by cycloheximide, indicating a protein mediator for the T 3 eVect. The T 3 stimulatory eVect was inhibited by anti-T 3 antibody suggesting specificity of T 3 action. Addition of T 3 caused a more than threefold increase in cellular protein synthesis which was inhibited by cycloheximide. Preparation of partially purified thyroid hormone-induced factor (TIF) (from peak II of Sephadex G 100 chromatography of T3-incubated cells), and its addition to luteal cell incubations caused a significant increase in P4 Release (P<0·05). Incubation with trypsin or treatment with heat destroyed the stimulatory eVect of TIF on P 4 Release, indicating the proteinaceous nature of TIF. Purified thyroid hormone-induced protein (TIP) from rat granulosa cells and fish ovarian follicles greatly stimulated P 4 Release from human luteal cells. These results suggest that T 3 stimulation of P 4 Release from human luteal cells is not direct, but is mediated through a putative protein factor, which appears to be a protein conserved through evolution as far as its biological activity is concerned.
D Schams - One of the best experts on this subject based on the ideXlab platform.
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oxytocin stimulates Progesterone Release from microdialyzed bovine corpus luteum in vitro
Biology of Reproduction, 1991Co-Authors: Akio Miyamoto, D SchamsAbstract:A microdialysis system (MDS) was implanted in corpora lutea (CL) from cows (Days 5-7, 8-12, and 15-18 of the estrous cycle); the CL were maintained in organ culture chambers. With this system, active substances can be applied, and a collection of steroids Released from luteal cells surrounding the microcapillary (cut-off point = 100 kDa) is possible, while luteal cells maintain cell-to-cell contact. Spontaneous pulses of Progesterone Release were observed in 90% of control (perfused with Ringer’s solution only) at 60-80-mm intervals. The infusion of bovine LH (bLH) for 20 mm (0.1-10 �ag/ml) stimulated dose-dependent Release of Progesterone. Both results indicate that the CL maintains the activity of Progesterone Release and the ability to respond to Ut stimulation in this system. Oxytocin (1-100 �M) also stimulated Progesterone Release in a dose-dependent manner. Preexposure with oxytocin antagonist blocked the stimulatory effect of oxytocin (p < 0.01) but not of LH (� < 0.05), confirming the specificity of the effect. When CL were prestimulated with a low dose of oxytocin (1 �M, 20 min) twice before bLH application, the Release of Progesterone by bLH (1 �g/m1, 20 min) was more pronounced (p < 0.05). A long-term infusion (3 h) with oxytocin and/or bLH stimulated the Release of Progesterone for the whole period of time. Oxytocin was most stimulative during the early luteal phase (Days 5-7) and decreased continuously from Days 8-12 to Days 15-18. The acute stimulatory effect on Progesterone Release by oxytocin described here has not been reported in studies using dispersed luteal cell incubations. Therefore, the overall results of this study suggest that cell-to-cell contact is important for the luteal response to oxytocin and support the hypothesis that ovarian oxytocin is involved in mechanisms of Progesterone secretion as an autocrine/paracrine factor, especially during the early luteal phase.
Salvatore Mancuso - One of the best experts on this subject based on the ideXlab platform.
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effects of nicotine on human luteal cells in vitro a possible role on reproductive outcome for smoking women
Biology of Reproduction, 2005Co-Authors: Fiorella Miceli, Anna Tropea, Francesca Minici, Federica Tiberi, Mariateresa Orlando, Stefania Catino, Giuseppina Lamanna, Francesca Sagnella, Adriano Bompiani, Salvatore MancusoAbstract:Abstract We investigated the effect of nicotine and its methylated metabolite, N-methyl-nicotine (M-nicotine), on human luteal cells by measuring Release of Progesterone and prostaglandins (PGs) from cultured cells and by testing gene expression of vascular endothelial growth factor (VEGF), an angiogenic factor strictly involved in luteal pathophysiology. Primary cultures of human luteal cells were treated for 24 h with nicotine and M-nicotine (from 10−6 to 10−11 M) either alone or combined with hCG (25 ng/ml); Progesterone and PGs were assayed in the culture medium. In another group of experiments, luteal cells were treated for 24 h with nicotine and M-nicotine (10−7 M) to perform reverse transcriptase-polymerase chain reaction on VEGF mRNA. Nicotine and M-nicotine negatively affected basal luteal steroidogenesis at all tested concentrations, but neither was able to affect hCG-induced Progesterone Release. Both substances were able to significantly increase PGF2α Release from luteal cells, with a dose-re...
Dariusz J Skarzynski - One of the best experts on this subject based on the ideXlab platform.
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role of intraluteal prostaglandin f2α Progesterone and oxytocin in basal and pulsatile Progesterone Release from developing bovine corpus luteum
Prostaglandins & Other Lipid Mediators, 2006Co-Authors: Tomas J Acosta, Wojciech Pilawski, Katarzyna M Deptula, Kiyoshi Okuda, Dariusz J SkarzynskiAbstract:Abstract The present study examined the role of intra-luteal prostaglandin (PG) F 2α , Progesterone (P4) and oxytocin (OT) on the corpus luteum function by using specific hormone antagonists. Luteal cells from the developing CL (days 5–7 of the estrous cycle) were exposed to P4 antagonist (onapristone, OP, 10 −4 M), OT antagonist (atosiban, AT; 10 −6 M) or indomethacin (INDO; 10 −4 M), for 12 h and then stimulated with PGF 2α (10 −8 M) for 4 h. Pre-treatment of the cells with OP, AT or INDO resulted in an increase in P4 secretion in response to PGF 2α . To examine the temporal effects of P4, OT and PGs on P4 secretion, dispersed luteal cells were pre-exposed to OP, AT or INDO for 1, 2, 4, 6 or 12 h. Prostaglandin F 2α stimulated P4 secretion ( P P P 2α , OT, and P4 are components of an autocrine/paracrine intra-ovarian regulatory system responsible for the episodic (pulsatile) Release of P4 from the bovine CL during the early luteal phase.