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Kiyoshi Okuda - One of the best experts on this subject based on the ideXlab platform.
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galectin 3 contributes to luteolysis by binding to beta 1 integrin in the bovine corpus luteum
Biology of Reproduction, 2014Co-Authors: Kazuhisa Hashiba, Dariusz J Skarzynski, Masahiro Sano, Junko Niokobayashi, Takuo Hojo, Kiyoshi OkudaAbstract:ABSTRACT Luteolysis is characterized by a reduction in progesterone (P4) production and tissue degeneration in the corpus luteum (CL). One of major events during luteolysis is luteal cell death. Galectin-3, a ubiquitously expressed protein involved in many cellular processes, serves as an antiapoptotic and/or proapoptotic factor in various cell types. Although galectin-3 is detected in the bovine CL, its role remains unclear. The expression of galectin-3 in the bovine CL was higher at the regressed stage than at the other luteal stages. Galectin-3 was localized on luteal steroidogenic cells (LSCs). When cultured LSCs were exposed to Prostaglandin F2alpha (PGF) for 48 h, the expression and secretion of galectin-3 increased. When the cultured LSCs were treated with galectin-3 for 24 h, cleaved caspase-3 expression was increased, and the cell viability was decreased, whereas P4 production did not change. Beta 1 integrin, a target protein of galectin-3, was expressed in bovine CL and possessed glycans, which ...
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roles of Prostaglandin F2alpha and hydrogen peroxide in the regulation of copper zinc superoxide dismutase in bovine corpus luteum and luteal endothelial cells
Reproductive Biology and Endocrinology, 2012Co-Authors: Tomas J Acosta, Shin Yoshioka, Hironori Abe, Kiyoshi OkudaAbstract:Background Prostaglandin F2alpha (PGF) induces luteolysis in cow by inducing a rapid reduction in progesterone production (functional luteolysis) followed by tissue degeneration (structural luteolysis). However the mechanisms of action of PGF remain unclear. Reactive oxygen species (ROS) play important roles in regulating the luteolytic action of PGF. The local concentration of ROS is controlled by superoxide dismutase (SOD), the main enzyme involved in the control of intraluteal ROS. Thus SOD seems to be involved in luteolysis process induced by PGF in cow.
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roles of Prostaglandin F2alpha and hydrogen peroxide in the regulation of copper zinc superoxide dismutase in bovine corpus luteum and luteal endothelial cells
Reproductive Biology and Endocrinology, 2012Co-Authors: Hai V Vu, Tomas J Acosta, Shin Yoshioka, Kiyoshi OkudaAbstract:Background: Prostaglandin F2alpha (PGF) induces luteolysis in cow by inducing a rapid reduction in progesterone production (functional luteolysis) followed by tissue degeneration (structural luteolysis). However the mechanisms of action of PGF remain unclear. Reactive oxygen species (ROS) play important roles in regulating the luteolytic action of PGF. The local concentration of ROS is controlled by superoxide dismutase (SOD), the main enzyme involved in the control of intraluteal ROS. Thus SOD seems to be involved in luteolysis process induced by PGF in cow. Methods: To determine the dynamic relationship between PGF and ROS in bovine corpus luteum (CL) during luteolysis, we determined the time-dependent change of Copper/Zinc SOD (SOD1) in CL tissues after PGF treatment in vivo. We also investigated whether PGF and hydrogen peroxide (H2O2) modulates SOD1 expression and SOD activity in cultured bovine luteal endothelial cells (LECs) in vitro. Results: Following administration of a luteolytic dose of PGF analogue (0 h) to cows at the mid-luteal stage, the expression of SOD1 mRNA and protein, and total SOD activity in CL tissues increased between 0.5 and 2 h, but fell below the initial (0 h) level at 24 h post-treatment. In cultured LECs, the expression of SOD1 mRNA was stimulated by PGF (1–10 microM) and H2O2 (10–100 microM) at 2 h (P<0.05). PGF and H2O2 increased SOD1 protein expression and total SOD activity at 2 h (P<0.05), whereas PGF and H2O2 inhibited SOD1 protein expressions and total SOD activity at 24 h (P<0.05). In addition, H2O2 stimulated PGF biosynthesis at 2 and 24 h in bovine LECs. Overall results indicate that, SOD is regulated by PGF and ROS in bovine LECs. SOD may play a role in controlling intraluteal PGF and ROS action during functional and structural luteolysis in cows.
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inter and intra cellular mechanisms of Prostaglandin F2alpha action during corpus luteum regression in cattle
Reproduction in domestic ruminants VII. Proceedings of the Eighth International Symposium on Reproduction in Domestic Ruminants Anchorage Alaska Septe, 2010Co-Authors: Dariusz J Skarzynski, Kiyoshi OkudaAbstract:The bovine corpus luteum (CL) grows very fast and regresses within a few days at luteolysis. Mechanisms controlling development and secretory function of the bovine CL may involve many factors that are produced both within and outside the CL. In the cow, luteolysis is initiated by uterine Prostaglandin (PG)F2alpha released at the late luteal stage. It can also be induced by injection of exogenous PGF2alpha given at the mid luteal stage. Luteolysis consists of a phase of rapid decrease in progesterone (P4) production by the CL, followed by a phase of structural regression. Although uterine PGF2alpha is known to be the main luteolytic factor, its direct action on the CL is mediated by the products of accessory luteal cells: immune cells, endothelial cells, pericytes and fibroblasts. There are studies showing that beside endothelin-1, cytokines (tumor necrosis factor-alpha, interferons) and nitric oxide play critical roles in functional and structural luteolysis in cattle by stimulating leukotrienes and PGF2alpha', decreasing P4 secretion and apoptosis induction. Because of luteal blood flow and P4 concentrations decrease in parallel during both spontaneous and PGF2alpha-induced luteolysis, a decrease in luteal blood flow resulting in hypoxia has been proposed as one of the main luteolytic mechanisms in the cow. Hypoxia inhibits P4 synthesis in luteal cells by inhibiting the steroidogenic enzymes and promotes apoptosis of luteal cells by increasing pro-apoptotic proteins. Although reduction of luteal blood flow and hypoxia contribute to the late events of luteolysis, little is known about the physiological relevance and the cause of the transient increase in luteal blood flow and reactive oxygen species during the initial step of luteolysis.
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Prostaglandin F2alpha stimulates 11beta hydroxysteroid dehydrogenase 1 enzyme bioactivity and protein expression in bovine endometrial stromal cells
Biology of Reproduction, 2009Co-Authors: Hwayong Lee, Tomas J Acosta, Dariusz J Skarzynski, Kiyoshi OkudaAbstract:Beta-hydroxysteroid dehydrogenase (HSD11B) enzymes have important roles in regulating cortisol availability in target tissues. We previously demonstrated that HSD11B1 is expressed and active in bovine endometrium and that cortisol suppresses Prostaglandin (PG) F2alpha and PGE2 production in cultured bovine endometrial stromal cells. The present study was conducted to examine whether locally synthesized PGF2alpha and/or PGE2 regulates the enzymatic bioactivity and/or the expression of HSD11B1 in bovine endometrium. The conversion rate of cortisone to cortisol in cultured endometrial stromal cells was significantly stimulated by PGF2alpha (1 and 10 lM). In a dose-dependent manner, PGF2alpha but not PGE2 increased the net conversion of cortisone to cortisol in stromal cells after 4 h of treatment. In addition, the bioactivity of HSD11B1 was significantly inhibited by indomethacin (10 lM). The inhibitory effect of indomethacin on HSD11B1 bioactivity was abolished by PGF2alpha (1 lM) but not by PGE2. Although PGF2alpha (1 lM) did not affect the expression of HSD11B1 mRNA in cultured stromal cells, it significantly stimulated the protein expression of HSD11B1. Cycloheximide, a general translational inhibitor, abolished the stimulatory effects of PGF2alpha on HSD11B1 protein expression in endometrial stromal cells, indicating that PGF2alpha increases HSD11B1 protein expres- sion by stimulating a posttranscriptional process rather than a transcriptional mechanism. These results demonstrate that PGF2alpha but not PGE2 increases HSD11B1 bioactivity and protein expression by stimulating a posttranscriptional mecha- nism in stromal cells and suggest that cortisol has a physiolog- ically relevant role in preventing excessive uterine PG production in nonpregnant bovine endometrium. cattle, cortisol, endometrium, HSD11B1, Prostaglandins, uterus
O.j. Ginther - One of the best experts on this subject based on the ideXlab platform.
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plasma clearance and half life of Prostaglandin F2alpha a comparison between mares and heifers
Biology of Reproduction, 2012Co-Authors: Hemanta K Shrestha, M A Beg, Ronald R Burnette, O.j. GintherAbstract:Horses are about five times more sensitive to the luteolytic effect of Prostaglandin F2alpha (PGF) than cattle, as indicated by a recommended clinical dose of 5 mg in horses and 25 mg in cattle. Novel evaluations of the PGF plasma disappearance curves were made in mares and in heifers, and the two species were compared. Mares and heifers (n ¼5) of similar body weight were injected (Min 0) intravenously with PGF (5 mg per animal). Blood was sampled every 10 sec until Min 3, every 30 sec until Min 5, every 10 min until Min 60, and every 30 min until Min 240. The mean PGF concentration was greater (P , 0.05) in mares than in heifers at Min 1 through Min 60 and at Mins 180 and 240. The mean time to maximum PGF concentration was not different between mares (42.0 6 8.6 sec) and heifers (35.0 6 2.9 sec). The apparent plasma clearance, distribution halflife, elimination half-life, and maximum plasma PGF concentration were 3.3 6 0.5 L h � 1 kg � 1 , 94.2 6 15.9 sec, 25.9 6 5.0 min, and 249.1 6 36.8 ng/ml, respectively, in mares and 15.4 6 2.3 L h � 1 kg � 1 , 29.2 6 3.9 sec, 9.0 6 0.9 min, and 51.4 6 22.6 ng/ml, respectively, in heifers. Plasma clearance was about five times less (P , 0.0005), maximum plasma PGF concentration was five times greater (P , 0.002), and the distribution half-life and elimination half-life were about three times longer (P , 0.005) in mares than in heifers. The fivefold greater plasma clearance of PGF in heifers than in mares corresponds to the recommended fivefold greater clinical dose of PGF in cattle and supported the hypothesis that the metabolic clearance of PGF is slower in mares than heifers.
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dynamics of circulating progesterone concentrations before and during luteolysis a comparison between cattle and horses
Biology of Reproduction, 2012Co-Authors: O.j. GintherAbstract:ABSTRACT The profile of circulating progesterone concentration is more dynamic in cattle than in horses. Greater prominence of progesterone fluctuations in cattle than in horses reflect periodic interplay in cattle between pulses of a luteotropin (luteinizing hormone; LH) and pulses of a luteolysin (Prostaglandin F2alpha; PGF2alpha). A dose of PGF2alpha that induces complete regression of a mature corpus luteum with a single treatment in cattle or horses is an overdose. The overdose effects on the progesterone profile in cattle are an immediate nonphysiological increase taking place over about 30 min, a decrease to below the original concentration, a dose-dependent rebound 2 h after treatment, and a progressive decrease until the end of luteolysis. An overdose of PGF2alpha in horses results in a similar nonphysiological increase in progesterone followed by complete luteolysis; a rebound does not occur. An overdose of PGF2alpha and apparent lack of awareness of the rebound phenomenon has led to faulty inte...
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characteristics of pulses of 13 14 dihydro 15 keto Prostaglandin F2alpha before during and after spontaneous luteolysis and temporal intrapulse relationships with progesterone concentrations in cattle
Biology of Reproduction, 2010Co-Authors: O.j. Ginther, H K Shrestha, M J Fuenzalida, A K M ShahiduzzamanAbstract:Pulses of the Prostaglandin F2alpha (PGF) metabolite 13,14dihydro-15-keto-PGF (PGFM) were compared among heifers that were in the preluteolytic, luteolytic, and postluteolytic periods (n ¼ 7 or 8 heifers/period). Hourly blood sampling was done in 18-h sessions 15, 16, or 17 days after ovulation. Hourly sampling and statistical identification of a PGFM pulse allowed novel comparisons of PGFM pulses among the three periods. Each period had a similar number of PGFM pulses (2.3 6 0.2). The pulses were more prominent during the luteolytic period than during the other periods, as indicated by significantly greater concentration for the peak and amplitude between nadir and peak. Significantly more fluctuations that did not meet the definition of a pulse occurred at the beginning of the preluteolytic period and end of the postluteolytic period than during the luteolytic period. The same nadir ended a pulse and began the next pulse in 85% of adjacent pulses. Seven heifers were selected objectively, based on a progesterone concentration .5 ng/ml at Hour � 3 (Hour 0 ¼ peak of PGFM pulse) and a progressive decrease in progesterone from Hours � 3t o 0. Progesterone increased (P , 0.03) between Hours 0 and 1, remained at a mean plateau at Hours 1 and 2, and then decreased. Results support the hypothesis of a transient intrapulse rebound in progesterone during an individual PGFM pulse, but only during the first portion of luteolysis. These findings should be considered in future proposals on the mechanisms involved in the effects of PGF on progesterone concentrations. corpus luteum, female reproductive tract, ovary, PGFM, progesterone
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necessity of sequential pulses of Prostaglandin F2alpha for complete physiologic luteolysis in cattle
Biology of Reproduction, 2009Co-Authors: O.j. Ginther, R R Araujo, M P Palhao, B L RodriguesAbstract:The luteolytic effects of exogenous Prostaglandin F2alpha (PGF) that did and did not simulate natural 13,14-dihydro-15-keto-PGF (PGFM) pulses were studied during mid-diestrus in 42 Holstein heifers. Plasma concentrations of PGF were assessed by assay of PGFM. In experiment 1, a single intrauterine injection of 4.0 mg of PGF into the uterine horn ipsilateral to the corpus luteum resulted in a precipitous progesterone decline, whereas sequential injections of 0.25 or 1.0 mg every 12 h resulted in a stepwise decrease (P < 0.05) following each injection. A progesterone increase occurred during the first 5 min before the luteolytic decrease but only for the 4.0-mg dose. From the results of experiment 2, a 2-h intrauterine infusion of a total of 0.5 mg of PGF was judged to best simulate a natural PGFM pulse. In experiment 3, simulation of sequential pulses at 12-h intervals resulted in a continuous precipitous decrease in progesterone to <1 ng/ml by the beginning of the fourth simulated pulse. In contrast, a single simulated pulse resulted in a 6-h progesterone decrease to a constant concentration for 3 days after treatment, followed by a return to control concentrations. The mean ± SEM interval between the pretreatment and posttreatment ovulations was shorter (P < 0.05) in the group with sequential simulated pulses (14 ± 1 day) than in the group with a single pulse (21 ± 1 day). Results indicated that excessive PGF doses may stimulate nonphysiologic progesterone responses and supported the hypothesis that sequential PGF pulses are required to stimulate natural luteolysis in cattle.
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temporal associations among pulses of 13 14 dihydro 15 keto pgF2alpha luteal blood flow and luteolysis in cattle
Biology of Reproduction, 2007Co-Authors: O.j. Ginther, Luciano Andrade Silva, R R AraujoAbstract:Abstract Luteal blood flow was studied in heifers by transrectal color-Doppler ultrasound. Data were normalized to the decrease in plasma progesterone to <1 ng/ml (Day 0 or Hour 0). Blood flow in the corpus luteum (CL) was estimated by the percentage of CL area with color flow signals. Systemic Prostaglandin F2alpha (PGF) treatment (25 mg; n = 4) resulted in a transient increase in CL blood flow during the initial portion of the induced decrease in progesterone. Intrauterine treatment (1 or 2 mg) was done to preclude hypothetical secondary effects of systemic treatment. Heifers were grouped into responders (luteolysis; n = 3) and nonresponders (n = 5). Blood flow increased transiently in both groups; induction of increased blood flow did not assure the occurrence of luteolysis. A transient increase in CL blood flow was not detected in association with spontaneous luteolysis when examinations were done every 12 h (n = 6) or 24 h (n = 10). The role of PGF pulses was studied by examinations every hour during...
Mariusz P Kowalewski - One of the best experts on this subject based on the ideXlab platform.
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biosynthesis and degradation of canine placental Prostaglandins prepartum changes in expression and function of Prostaglandin F2alpha synthase pgfs akr1c3 and 15 hydroxyProstaglandin dehydrogenase hpgd
Biology of Reproduction, 2013Co-Authors: Aykut Gram, Urs Buchler, Alois Boos, Mariusz P KowalewskiAbstract:ABSTRACT There is no distinct explanation of the mechanism for the prepartal Prostaglandin F2alpha (PGF2alpha) increase in pregnant dogs. Although the PGF2alpha-synthase (PGFS [AKR1C3]) mRNA expression and localization profiles have been previously investigated in canine utero/placental compartments, the availability and biochemical activity of the PGFS (AKR1C3) protein remain unknown. In order to better understand the regulation of canine uterine PGF2alpha availability and eventual prepartum release in luteolytic amounts in dogs, canine-specific PGFS (AKR1C3) and 15-hydroxyProstaglandin dehydrogenase (HPGD) antibodies were generated and used to characterize the expression, cellular localization, and biochemical properties of PGFS (AKR1C3) and HPGD in the utero/placental compartments and corpus luteum throughout pregnancy and at prepartum luteolysis. PGFS (AKR1C3) expression was weak or absent in luteal samples. Uterine PGFS (AKR1C3) was up-regulated postimplantation and declined prepartum. The utero/plac...
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biosynthesis and degradation of canine placental Prostaglandins prepartum changes in expression and function of Prostaglandin F2alpha synthase pgfs akr1c3 and 15 hydroxyProstaglandin dehydrogenase hpgd
Biology of Reproduction, 2013Co-Authors: Aykut Gram, Urs Buchler, Alois Boos, B Hoffmann, Mariusz P KowalewskiAbstract:There is no distinct explanation of the mechanism for the prepartal Prostaglandin F2alpha (PGF2alpha) increase in pregnant dogs. Although the PGF2alpha-synthase (PGFS [AKR1C3]) mRNA expression and localization profiles have been previously investigated in canine utero/placental compartments, the availability and biochemical activity of the PGFS (AKR1C3) protein remain unknown. In order to better understand the regulation of canine uterine PGF2alpha availability and eventual prepartum release in luteolytic amounts in dogs, canine-specific PGFS (AKR1C3) and 15-hydroxyProstaglandin dehydrogenase (HPGD) antibodies were generated and used to characterize the expression, cellular localization, and biochemical properties of PGFS (AKR1C3) and HPGD in the utero/placental compartments and corpus luteum throughout pregnancy and at prepartum luteolysis. PGFS (AKR1C3) expression was weak or absent in luteal samples. Uterine PGFS (AKR1C3) was up-regulated postimplantation and declined prepartum. The utero/placental expression of PGFS (AKR1C3) was identified in the superficial uterine glands throughout gestation and in the trophoblast cells within the feto-maternal contact zone during placentation, suggesting a possible role for PGFS (AKR1C3) in the trophoblast invasion. Utero-placental HPGD was up-regulated until postimplantation, lower at midgestation, and greatly suppressed at prepartum. Expression was routinely identified in the endometrial surface and glandular epithelia, and positive signals were also observed in the trophoblast cells at the feto-maternal contact zone. The biochemical activity of recombinant PGFS (AKR1C3) and HPGD was confirmed after its expression in a heterologous system. The colocalization of HPGD with PGFS (AKR1C3) expression suggests a modulatory role for HPGD as a gatekeeper of the supply of Prostaglandin in the pregnant canine uterus.
Aykut Gram - One of the best experts on this subject based on the ideXlab platform.
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biosynthesis and degradation of canine placental Prostaglandins prepartum changes in expression and function of Prostaglandin F2alpha synthase pgfs akr1c3 and 15 hydroxyProstaglandin dehydrogenase hpgd
Biology of Reproduction, 2013Co-Authors: Aykut Gram, Urs Buchler, Alois Boos, Mariusz P KowalewskiAbstract:ABSTRACT There is no distinct explanation of the mechanism for the prepartal Prostaglandin F2alpha (PGF2alpha) increase in pregnant dogs. Although the PGF2alpha-synthase (PGFS [AKR1C3]) mRNA expression and localization profiles have been previously investigated in canine utero/placental compartments, the availability and biochemical activity of the PGFS (AKR1C3) protein remain unknown. In order to better understand the regulation of canine uterine PGF2alpha availability and eventual prepartum release in luteolytic amounts in dogs, canine-specific PGFS (AKR1C3) and 15-hydroxyProstaglandin dehydrogenase (HPGD) antibodies were generated and used to characterize the expression, cellular localization, and biochemical properties of PGFS (AKR1C3) and HPGD in the utero/placental compartments and corpus luteum throughout pregnancy and at prepartum luteolysis. PGFS (AKR1C3) expression was weak or absent in luteal samples. Uterine PGFS (AKR1C3) was up-regulated postimplantation and declined prepartum. The utero/plac...
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biosynthesis and degradation of canine placental Prostaglandins prepartum changes in expression and function of Prostaglandin F2alpha synthase pgfs akr1c3 and 15 hydroxyProstaglandin dehydrogenase hpgd
Biology of Reproduction, 2013Co-Authors: Aykut Gram, Urs Buchler, Alois Boos, B Hoffmann, Mariusz P KowalewskiAbstract:There is no distinct explanation of the mechanism for the prepartal Prostaglandin F2alpha (PGF2alpha) increase in pregnant dogs. Although the PGF2alpha-synthase (PGFS [AKR1C3]) mRNA expression and localization profiles have been previously investigated in canine utero/placental compartments, the availability and biochemical activity of the PGFS (AKR1C3) protein remain unknown. In order to better understand the regulation of canine uterine PGF2alpha availability and eventual prepartum release in luteolytic amounts in dogs, canine-specific PGFS (AKR1C3) and 15-hydroxyProstaglandin dehydrogenase (HPGD) antibodies were generated and used to characterize the expression, cellular localization, and biochemical properties of PGFS (AKR1C3) and HPGD in the utero/placental compartments and corpus luteum throughout pregnancy and at prepartum luteolysis. PGFS (AKR1C3) expression was weak or absent in luteal samples. Uterine PGFS (AKR1C3) was up-regulated postimplantation and declined prepartum. The utero/placental expression of PGFS (AKR1C3) was identified in the superficial uterine glands throughout gestation and in the trophoblast cells within the feto-maternal contact zone during placentation, suggesting a possible role for PGFS (AKR1C3) in the trophoblast invasion. Utero-placental HPGD was up-regulated until postimplantation, lower at midgestation, and greatly suppressed at prepartum. Expression was routinely identified in the endometrial surface and glandular epithelia, and positive signals were also observed in the trophoblast cells at the feto-maternal contact zone. The biochemical activity of recombinant PGFS (AKR1C3) and HPGD was confirmed after its expression in a heterologous system. The colocalization of HPGD with PGFS (AKR1C3) expression suggests a modulatory role for HPGD as a gatekeeper of the supply of Prostaglandin in the pregnant canine uterus.
R Meidan - One of the best experts on this subject based on the ideXlab platform.
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regulation of angiogenesis related Prostaglandin F2alpha induced genes in the bovine corpus luteum
Biology of Reproduction, 2012Co-Authors: Yulia Zalman, Eyal Klipper, Svetlana Farberov, Mohan Mondal, Joseph K Folger, George W Smith, Gabbine Wee, R MeidanAbstract:We recently compared Prostaglandin F2alpha (PG)-induced global gene expression profiles in PG-refractory, bovine corpus luteum (CL) collected on Day 4 of the estrous cycle, versus PG-responsive, Day 11 CL. Transcriptome analyses led us to study the regulation of angiogenesis-related genes by PG and their functions in luteal endothelial cells (ECs). We found that PG regulated angiogenesis-modulating factors in a luteal stage-dependent way. A robust increase in FGF2 expression (mRNA and protein) occurred in the PG-refractory Day 4 CL promoting CL survival and function. Inhibitors of FGF2 action, thrombospondin 1 and 2, their receptor (CD36), and PTX3 were upregulated by PG specifically in Day 11 CL undergoing luteolysis. VEGF mRNA decreased 4 h post-PG in both Day 4 and Day 11 CL. The resulting destabilization of blood vessels in Day 11 CL is expected to weaken the gland and reduce its hormonal output. These genes were expressed in dispersed luteal ECs and steroidogenic cells; however, thrombospondin 1 and FGF2 were more abundant in luteal ECs. Expression of such genes and their ability to modulate FGF2 actions were investigated. Similar to its in vivo effect, PG, in vitro, stimulated the expression of thrombospondins and PTX3 genes in several luteal cell models. Importantly, these factors influenced the angiogenic properties of luteal ECs. FGF2 dose-dependently enhanced cell migration and proliferation, whereas thrombospondin 1 and PTX3 inhibited FGF2 actions in luteal ECs. Collectively, the data presented here suggest that, by tilting the balance between pro- and antiangiogenic factors, PG can potentially control the ability of the CL to resist or advance toward luteolysis.
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effect of endothelin 1 on bovine luteal cell function role in Prostaglandin F2alpha induced antisteroidogenic action
Endocrinology, 1996Co-Authors: Eliezer Girsh, R A Milvae, W Wang, R MeidanAbstract:Endothelin-1 (ET-1) a vasoactive peptide, is synthesized and secreted by endothelial cells. In the bovine corpus luteum (CL), endothelial cells constitute a major proportion (53.5%) of total CL cells. This study was designed to examine the effects of ET-1 on bovine luteal cell functions and its involvement in the action of PGF2alpha. To better define the cells implicated in this process, we used CL slices, whole CL-derived cells, and steroidogenic large (LLC) and small (SLC) luteal-like cells. High affinity binding sites for ET-1 (K(d), approximately 0.3 x 10(-9)) were present in both steroidogenic luteal cells. The binding affinity of ET-1 was 3 orders of magnitude higher than that of ET-3, and a selective ETA receptor antagonist (BQ123) competed similarly to ET-1, suggesting the presence of ETA receptors. The lack of effect of ET-3 on CL-derived cells further supported this conclusion. Both basal progesterone secretion and bovine LH (5 ng/ml)-stimulated progesterone secretion from CL-derived cells were ...
