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Kurusu S, Sonoda N, Nakahara M, Yonezawa T, Kawaminami M. Evidence suggesting multiple promoting roles of luteal group IVA phospholipase A(2) in prostaglandin F(2alpha)-induced regression in pseudopregnant rats. Prostaglandins Other Lipid Mediat 2010; 93:37-43. [PMID: 20601072 DOI: 10.1016/j.prostaglandins.2010.06.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Revised: 05/28/2010] [Accepted: 06/14/2010] [Indexed: 12/31/2022]
Abstract
We evaluated effects of local administration of selective inhibitors of group IVA phospholipase A(2) (GIVA PLA(2)) and cyclooxygenase (COX) on exogenous prostaglandin (PG) F(2alpha)-induced luteal regression in pseudopregnant rats. Intra-bursal treatment with a GIVA PLA(2) inhibitor AACOCF(3) just prior to PGF(2alpha) (30microg, subcutaneously) on day 6 of pseudopregnancy (PSP6) prevented a decline in circulating progesterone and inhibited TUNEL-positive reactions of steroidogenic cell. Its treatment on PSP9 failed to inhibit functional regression, but reduced significantly apoptosis of steroidogenic cells and vascular endothelial cells, and suppressed the infiltration of macrophages. A COX-2-selective inhibitor NS398 inhibited the decline of progesterone and apoptosis of steroidogenic cells on PSP6 but not on PSP9. A COX-1 inhibitor SC560 exerted insignificant anti-luteolytic effects. Overall data suggest that luteal GIVA PLA(2) plays multiple promoting roles in PGF(2alpha)-induced luteal regression at least partly by a COX-2 activity-related mechanism in pseudopregnant rats.
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Affiliation(s)
- Shiro Kurusu
- Laboratory of Veterinary Physiology, Kitasato University School of Veterinary Medicine, Higashi 23-35-1, Towada, Aomori 034-8628, Japan.
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Kurusu S, Tokunaga N, Yonezawa T, Kawaminami M. Group IVA phospholipase A(2) activity may mediate prostaglandin F(2alpha)-induced luteal regression in pseudopregnant rats. Prostaglandins Other Lipid Mediat 2009; 90:55-62. [PMID: 19703580 DOI: 10.1016/j.prostaglandins.2009.08.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2009] [Revised: 08/07/2009] [Accepted: 08/10/2009] [Indexed: 01/26/2023]
Abstract
We investigated role(s) of luteal group IVA phospholipase A(2) (GIVA PLA(2)) in prostaglandin (PG) F(2alpha)-induced regression in pseudopregnant rats. Prostaglandin F(2alpha) (PGF(2alpha)) treatment of day 6 pseudopregnant rats stimulated luteal PLA(2) activity, which was sensitive to inhibitors and associated with increased GIVA PLA(2) immunoreactivity. Intra-bursal treatment with the enzyme inhibitor (AACOCF3) prior to PGF(2alpha) failed to prevent the initial decline in progesterone but induced subsequently a persistent rise that was significantly higher than that of vehicle-treated group. TUNEL-positive signals in luteal cells of control group were reduced by AACOCF3 treatment. TUNEL-positive reaction induced in luteal cells in vitro by combined cytokines and agonistic anti-Fas were both reduced by AACOCF3 and another inhibitor pyrrophenone. Overall data show that luteal GIVA PLA(2) activity and expression increased following PGF(2alpha) administration and that acute chemical inhibition of this activity could reverse, at least partly, PGF(2alpha)-induced functional regression and prevent apoptosis induced by PGF(2alpha)in vivo and by cytokines in vitro.
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Affiliation(s)
- Shiro Kurusu
- Laboratory of Veterinary Physiology, Kitasato University School of Veterinary Medicine, Towada, Aomori 034-8628, Japan.
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Kurusu S, Kamikubo M, Yonezawa T, Kawaminami M. Differential regulation of phospholipase A(2) activity and prostaglandin E(2) synthesis in activated and non-activated corpora lutea of lactation by the presence and absence of suckling stimulus in rats. Prostaglandins Other Lipid Mediat 2009; 90:26-30. [PMID: 19615458 DOI: 10.1016/j.prostaglandins.2009.07.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2009] [Revised: 06/24/2009] [Accepted: 07/07/2009] [Indexed: 10/20/2022]
Abstract
We investigated content of prostaglandin (PG) E(2), a luteotropic eicosanoid, and phospholipase A(2) (PLA(2)) activity in two distinct states of rat corpora lutea of lactation (LCL). Rats subjected to forced weaning on day 0 postpartum (PP0) had a significant attenuation of progesterone synthesis and LCL weight on PP6 and/or PP3 compared with normally lactating rats. Repeated administration of prolactin (10 IU, twice daily) to weaned rats reversed impaired LCL function and structural development beyond the normal level of lactating animals. From PP3 to PP6, PGE(2) level in lactating LCL was increased while it was not altered in non-lactating LCL. In contrast, PLA(2) activity in the cytosol plus microsome fractions was decreased in lactating LCL and was up-regulated in non-lactating LCL as early as on PP3. This study provides the first evidence for differential regulation of PLA(2) activity and PGE(2) synthesis in activation and activation failure of postpartum CL in rats.
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Affiliation(s)
- Shiro Kurusu
- Laboratory of Veterinary Physiology, Kitasato University School of Veterinary Medicine, Towada, Aomori 034-8628, Japan.
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Abstract
Cells living under aerobic conditions always face oxygen paradox. Oxygen is necessary for cells to maintain their lives. However, reactive oxygen species such as superoxide radical ( ), hydroxyl radical (OH-) and hydrogen peroxide (H2O2) are generated from oxygen and damage cells. Oxidative stress occurs as a consequence of excessive production of reactive oxygen species and impaired antioxidant defense systems. Antioxidant enzymes include: superoxide dismutase (SOD), which is a specific enzyme to scavenge superoxide radicals; copper-zinc SOD, located in the cytosol; and manganese SOD, located in the mitochondria. Both types of SOD belong to the first enzymatic step to scavenge superoxide radicals. It has been reported that a number of local factors such as cytokines, growth factors and eicosanoids are involved in the regulation of ovarian function, in addition to gonadotropins and ovarian steroid hormones. Since reactive oxygen species are generated and SOD is expressed in the ovary, there is a possibility that reactive oxygen species and SOD work as local regulators of ovarian function. The present review reports that reactive oxygen species and their scavenging systems play important roles in several processes of reproductive physiology, including follicular development, oocyte maturation, ovulation, corpus luteum function and follicular atresia. (Reprod Med Biol 2005; 4: 31- 45).
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Affiliation(s)
- Norihiro Sugino
- Division of Obstetrics and Gynecology, Department of Reproductive, Pediatric and Infectious Science, Yamaguchi University School of Medicine, Minamikogushi, Ube, Japan
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Wiltbank MC, Ottobre JS. Regulation of intraluteal production of prostaglandins. Reprod Biol Endocrinol 2003; 1:91. [PMID: 14613533 PMCID: PMC293427 DOI: 10.1186/1477-7827-1-91] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2003] [Accepted: 11/10/2003] [Indexed: 11/20/2022] Open
Abstract
There is clear evidence for intraluteal production of prostaglandins (PGs) in numerous species and under a variety of experimental conditions. In general, secretion of PGs appears to be elevated in the early corpus luteum (CL) and during the period of luteolysis. Regulation of intraluteal PG production is regulated by a variety of factors. An autoamplification pathway in which PGF-2alpha stimulates intraluteal production of PGF-2alpha has been identified in a number of species. The mechanisms underlying this autoamplification pathway appear to differ by species with expression of Cyclooxygenase-2 (Cox-2) and activity of phospholipase A2 acting as important physiological control points. In addition, a number of other responses that are induced by PGF-2alpha (decreased luteal progesterone, increased endothelin-1, increased cytokines) also have been found to increase intraluteal PGF-2alpha production. Thus, regulation of intraluteal PG production may serve to initiate or amplify physiological signals to the CL and may be important in specific aspects of luteal physiology particularly during luteal regression.
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Affiliation(s)
- Milo C Wiltbank
- University of Wisconsin, Madison Dairy Science Department, Madison, WI 53706, USA
| | - Joseph S Ottobre
- Ohio State University, Department of Animal Sciences, Columbus, OH 43210, USA
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Diaz FJ, Anderson LE, Wu YL, Rabot A, Tsai SJ, Wiltbank MC. Regulation of progesterone and prostaglandin F2alpha production in the CL. Mol Cell Endocrinol 2002; 191:65-80. [PMID: 12044920 DOI: 10.1016/s0303-7207(02)00056-4] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
After the luteinizing hormone (LH) surge, the cells that remain from the ovulated follicle undergo a process of differentiation termed luteinization. Two key features of the cells after luteinization are the capacity for tremendous production of progesterone [10(16) molecules of progesterone per (min/(g of CL))] and the capacity to undergo regression or death of the cells at the appropriate time. There are two steroidogenic cell types, the small and large luteal cells that are regulated by different mechanisms. In small luteal cells, production of progesterone is stimulated by LH through the protein kinase A (PKA) pathway. The large luteal cells of ruminants produce large quantities of progesterone that is independent of LH stimulation. Although luteotrophins clearly regulate luteal function, much of luteal progesterone production in some species appears to be constitutive, consistent with the autonomous aspects of the large luteal cell. The key regulated step in luteal progesterone production appears to be regulation of transport of cholesterol to the inner mitochondrial membrane apparently mediated by the steroidogenic acute regulatory protein (StAR). In addition, our recent research indicates that PKA is tonically active in large luteal cells and this may be responsible for the high, relatively autonomous nature of luteal progesterone production. Regression of the corpus luteum (CL) in many species is initiated by prostaglandin (PG) F2alpha secreted from the uterus. Luteal cells also have the capacity for production of PGF2alpha. Luteal PGF2alpha production can be regulated by a variety of substances including inhibition by progesterone and stimulation by cytokines. We have also characterized a positive feedback pathway in ruminant and porcine CL in which small amounts of uterine PGF(2alpha) stimulate intraluteal production of PGF2alpha due to induction of the cycloxygenase-2 (Cox-2) enzyme in large luteal cells. This positive feedback pathway is only present in CL that has acquired the capacity for luteal regression ( approximately day 7 in cow, approximately day 13 in pig). Regulation by protein kinase C (PKC) of transcriptional factors interacting with an E-box in the 5' flanking region of the Cox-2 gene is the critical regulatory element involved in this positive feedback pathway. Thus, luteinization in some species appears to change specific gene transcription such that progesterone production becomes relatively independent of acute luteotrophic regulation and intraluteal PGF2alpha synthesis is induced by the second messenger pathways that are activated by PGF2alpha.
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Affiliation(s)
- F J Diaz
- Endocrinology-Reproductive Physiology Program and Department of Dairy Science, University of Wisconsin-Madison, 236 Animal Sciences Building, 1675 Observatory Drive, Madison, WI 53706, USA
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Abayasekara DR, Wathes DC. Effects of altering dietary fatty acid composition on prostaglandin synthesis and fertility. Prostaglandins Leukot Essent Fatty Acids 1999; 61:275-87. [PMID: 10670689 DOI: 10.1054/plef.1999.0101] [Citation(s) in RCA: 147] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Several studies over the past 20 years have demonstrated that subjects on diets composed of substances with high levels of n-3 polyunsaturated fatty acids (PUFAs) (e.g. fish) have a decreased incidence of heart disease. On this basis, a recent report from the Department of Health has advised UK consumers to decrease the proportion of saturated as opposed to unsaturated fats in their diet and to increase the ratio of n-3 to n-6 PUFAs. This could be achieved by altering the amounts of these constituents in milk and meat. n-3 Fatty acids can most easily be added to animal feed as either fish oil or linseed oil and can be increased in the blood and milk of ruminants following protection to avoid hydrogenation in the rumen. In western countries the ratio of consumption of n-6 to n-3 PUFAs is greater than 10 and current evidence tends to suggest that a ratio nearer 5 would be more desirable and compatible with cardiovascular well being. As fertility in the UK dairy herd is already poor, it is important to establish whether alterations in dietary n-3 and n-6 PUFAs affects herd fertility before widespread changes in animal diets are recommended. Therefore, this review considers the role played by PUFAs and eicosanoids in fertility, with particular reference to the implications for farm livestock production. The evidence reviewed shows that alteration of the concentration and ratio of n-6 and n-3 PUFAs in feeds can influence prostaglandin synthesis/metabolism in a number of mammalian systems. The changed patterns of prostaglandin synthesis can as a consequence, affect the diverse functions (e.g. hormone secretion) that are normally mediated via prostaglandins. Similarly, changes in prostaglandin synthesis effected through manipulation of PUFAs has a major bearing on fertility (as PGs affect many reproductive parameters, e.g. ovulation). Several studies in cattle and other mammals, show that feeding or infusing different types of fat with varying PUFA content to females can alter: the number and size of ovarian follicles, the ovulation rate, progesterone production by the corpus luteum, the timing of luteolysis and gestational length. In the male most recent work has focussed on sperm production and experiments in fowl have demonstrated clear effects of dietary PUFAs on both the sperm membrane phospholipid composition and on fertilizing ability.
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Affiliation(s)
- D R Abayasekara
- Reproduction and Development Group, Department of Veterinary Basic Sciences, Royal Veterinary College, London, UK.
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Kurusu S, Tsukamoto K, Konishi H, Tachibana M, Kawaminami M, Hashimoto I. Biphasic change in correlation between ovarian lipid peroxides and progestational activity during pseudopregnancy induced in immature rats. J Vet Med Sci 1999; 61:1039-42. [PMID: 10535510 DOI: 10.1292/jvms.61.1039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We measured ovarian lipid peroxide (LP) levels and plasma progestins, progesterone (P4) and 20alpha-dihydroprogesterone, throughout pseudopregnancy in gonadotropin-primed immature rats. Plasma P4 fluctuated, with two peaks on days 5 (PSP5) and 8 of pseudopregnancy, and then declined to the basal level by PSP12. Ovarian LP increased from PSP1 to PSP4, decreased temporarily until PSP8, and then rose gradually until PSP14. From PSP1 through PSP7, ovarian LP was positively correlated with total progestins according to the Spearman ranked correlation coefficient (r=+0.829, p<0.05). In contrast, a negative correlation between ovarian LP and plasma P4 was apparent (r=-0.816, p<0.05) from PSP8 to PSP14. These results show the biphasic correlation of LP with luteal progestational activity depending on the luteal stage.
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Affiliation(s)
- S Kurusu
- Laboratory of Veterinary Physiology, Kitasato University School of Veterinary Medicine and Animal Sciences, Towada, Aomori, Japan
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Kurusu S, Kaizo K, Ibashi M, Kawaminami M, Hashimoto I. Luteal phospholipase A2 activity increases during functional and structural luteolysis in pregnant rats. FEBS Lett 1999; 454:225-8. [PMID: 10431812 DOI: 10.1016/s0014-5793(99)00389-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
We determined cytosolic phospholipase A2 activity of the corpus luteum during luteolysis in pregnant and post-partum rats. Phospholipase A2 activity and its metabolite prostaglandin F2alpha in the corpus luteum remarkably increased just before parturition and further rose transiently during post-partum structural luteolysis. The absence of a pups' suckling stimulus delayed corpus luteum involution, being associated with an altered fluctuation in phospholipase A2 activity and depressed prostaglandin F2alpha levels. Exogenous prolactin had a reversal effect. Pharmacological and immunochemical characterization suggests multiple isoforms of phospholipase A2 in a pregnant corpus luteum. These results show the increased phospholipase A2 activity and its possible implication in luteolysis in pregnant rats.
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Affiliation(s)
- S Kurusu
- Laboratory of Veterinary Physiology, Kitasato University School of Veterinary Medicine and Animal Sciences, Towada, Aomori, Japan.
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Aten RF, Kolodecik TR, Rossi MJ, Debusscher C, Behrman HR. Prostaglandin f2alpha treatment in vivo, but not in vitro, stimulates protein kinase C-activated superoxide production by nonsteroidogenic cells of the rat corpus luteum. Biol Reprod 1998; 59:1069-76. [PMID: 9780311 DOI: 10.1095/biolreprod59.5.1069] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Luteal regression is associated with the generation of reactive oxygen species (ROS). To determine the nature of the ROS generator, cells isolated from luteinized rat ovaries were examined for ROS production using luminol-amplified chemiluminescence (LCL). Cells cultured for 2-48 h exhibited minimal LCL, but there was a significant (30- to 50-fold), rapid (maximum at 3-5 min), and dose-dependent increase in LCL in response to phorbol ester (phorbol 12-myristate 13-acetate; TPA; ED50 = 0.03 microM) and diacylglycerol (1,2-dioctanoyl-glycerol; ED50 = 30 microM). The TPA-induced response was cell number dependent and was virtually abolished by superoxide dismutase, freezing, or heating (95 degrees C for 5 min). Zymosan, known to induce a phagocytic response in leukocytes, stimulated a superoxide (O2-.) response with a slow onset (maximum at 40 to 60 min) and a maximum about one third of that observed for TPA. The response to TPA and zymosan was inhibited by the NADPH/NADH-oxidase inhibitor, diphenylene iodonium (ID50 = 5 microM for TPA), but not by the mitochondrial inhibitors, potassium cyanide, rotenone, or sodium azide. Fractionation of cells by centrifugal elutriation showed that TPA-stimulated O2-. production coeluted with the nonsteroidogenic cells and that little, if any, O2-. generation coeluted with the steroidogenic cells. Cells isolated 1, 2, and 4 h after in vivo treatment with a luteolytic dose of prostaglandin F2alpha (PGF2alpha) showed a significant increase in TPA-stimulated O2-. production at 2 h, whereas luteal cells or corpora lutea incubated directly with 1 microM PGF2alpha did not show any increase in response. Corpora lutea isolated from naturally regressed ovaries (18 days after ovulation) showed a significantly elevated level of TPA-stimulated O2-. production. In conclusion, there is a superoxide generator in luteinized ovaries that is activated through a protein kinase C pathway, localized in nonsteroidogenic cells, transiently increased during PGF2alpha-induced luteolysis in vivo, and elevated during natural luteal regression.
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Affiliation(s)
- R F Aten
- Department of Obstetrics and Gynecology, Yale University School of Medicine, New Haven, Connecticut 06520-8063, USA.
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Kurusu S, Noguchi T, Kawaminami M, Hashimoto I. Role of cytosolic phospholipase A2 in eicosanoid generation by corpora lutea of pseudopregnant rats: effects of its specific inhibitor. Prostaglandins Leukot Essent Fatty Acids 1997; 57:119-24. [PMID: 9250694 DOI: 10.1016/s0952-3278(97)90001-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
This study was performed to investigate whether 85 kDa cytosolic phospholipase A2 (cPLA2) functions in eicosanoid generation in rat corpora lutea (CL) using its specific inhibitor, arachidonyl trifluoromethyl ketone (ATK). In both immature and adult pseudopregnant rats, PLA2 activity in the cytosol of CL, measured by the liposome-vesicle assay, increased from day 6 of pseudopregnancy (PSP6) to PSP12. 10 microM ATK potently inhibited all of these activities to 10-20% and the rate of the inhibition by ATK was much higher on PSP12. ATK also reduced arachidonic acid (AA) release from luteal cells of PSP12 prelabelled with 3H-AA. Furthermore, the production of prostaglandin E2 by cultured luteal cells was mostly suppressed by the drug. These results suggest the augmentation of cPLA2 activity with the luteal age of pseudopregnant rats and its principal role in eicosanoid generation in CL.
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Affiliation(s)
- S Kurusu
- Laboratory of Veterinary Physiology, Kitasato University School of Veterinary Medicine and Animal Sciences, Towada, Aomori, Japan.
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Townson DH, Pate JL. Mechanism of action of TNF-alpha-stimulated prostaglandin production in cultured bovine luteal cells. PROSTAGLANDINS 1996; 52:361-73. [PMID: 8948504 DOI: 10.1016/s0090-6980(96)00104-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Tumor necrosis factor-alpha (TNF-alpha) influences hormone synthesis of many ovarian cell types and can also exert cytotoxic effects, possibly by increasing the synthesis of prostaglandins. The purpose of the present study was to characterize the mechanism of TNF-alpha-stimulated prostaglandin; F2 alpha (PGF2 alpha) production in cultured bovine luteal cells. Inhibitors of RNA and protein synthesis (actinomycin D and cycloheximide, respectively) completely blocked TNF-alpha-stimulated PGF2 alpha production. The phospholipase A2 inhibitor, aristolochic acid, prevented TNF-alpha-stimulated, but not basal, PGF2 alpha production, whereas the phospholipase C inhibitor, compound 48/80, was without effect. The addition of arachidonic acid to cultures did not overcome the inhibitory effects of cycloheximide or aristolochic acid. In conclusion, TNF-alpha-stimulated prostaglandin production by bovine luteal cells is dependent upon the stimulation of phospholipase A2 through mechanisms which require synthesis of RNA and protein.
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Affiliation(s)
- D H Townson
- Department of Animal Sciences, Ohio State University, Columbus 43210 USA
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KURUSU S, HIRANO Y, KAWAGISHI S, KITABATAKE T, SUZUKI A, KAWAMINAMI M, HASHIMOTO I. Effects of Intra-ovarian Bursal Injection of Eicosanoid Synthesis Inhibitors on Luteal Function in Immature Pseudopregnant Rats. J Reprod Dev 1995. [DOI: 10.1262/jrd.41.21] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Shiro KURUSU
- Laboratory of Veterinary Physiology, Kitasato University School of Veterinery Medicine and Animal Sciences, Towada, Aomori 034, Japan
| | - Yumi HIRANO
- Laboratory of Veterinary Physiology, Kitasato University School of Veterinery Medicine and Animal Sciences, Towada, Aomori 034, Japan
| | - Saori KAWAGISHI
- Laboratory of Veterinary Physiology, Kitasato University School of Veterinery Medicine and Animal Sciences, Towada, Aomori 034, Japan
| | - Tsuzumi KITABATAKE
- Laboratory of Veterinary Physiology, Kitasato University School of Veterinery Medicine and Animal Sciences, Towada, Aomori 034, Japan
| | - Akinori SUZUKI
- Laboratory of Veterinary Physiology, Kitasato University School of Veterinery Medicine and Animal Sciences, Towada, Aomori 034, Japan
| | - Mitsumori KAWAMINAMI
- Laboratory of Veterinary Physiology, Kitasato University School of Veterinery Medicine and Animal Sciences, Towada, Aomori 034, Japan
| | - Inoru HASHIMOTO
- Laboratory of Veterinary Physiology, Kitasato University School of Veterinery Medicine and Animal Sciences, Towada, Aomori 034, Japan
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KURUSU S, SHINGAKI S, MUNEKATA Y, KAWAMINAMI M, HASHIMOTO I. Detection of Cytosolic Phospholipase A 2 (cPLA 2) in Rat Corpora Lutea: Relationship to Functional Luteolysis. J Reprod Dev 1995. [DOI: 10.1262/jrd.41.141] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Shiro KURUSU
- Laboratory of Veterinary Physiology, Kitasato University School of Veterinary Medicine and Animal Sciences, Towada, Aomori 034, Japan
| | - Satoshi SHINGAKI
- Laboratory of Veterinary Physiology, Kitasato University School of Veterinary Medicine and Animal Sciences, Towada, Aomori 034, Japan
| | - Yoshiko MUNEKATA
- Laboratory of Veterinary Physiology, Kitasato University School of Veterinary Medicine and Animal Sciences, Towada, Aomori 034, Japan
| | - Mitsumori KAWAMINAMI
- Laboratory of Veterinary Physiology, Kitasato University School of Veterinary Medicine and Animal Sciences, Towada, Aomori 034, Japan
| | - Inoru HASHIMOTO
- Laboratory of Veterinary Physiology, Kitasato University School of Veterinary Medicine and Animal Sciences, Towada, Aomori 034, Japan
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Abstract
The homeostasis and ephemerality of the corpus luteum (CL) involves an intriguing interplay amongst pituitary, placental and intraovarian regulators. Recent findings have indicated a local pathway of synthesis for the cyclooxygenase-derived prostaglandins (PGs) in luteal cells of all mammalian species investigated. Thus, an autocrine or paracrine role of intraluteal PGs in modulation of luteal steroidogenesis is implicated. The presence of immune cells in the ovary indicates a constitutive role of these cells and their secretory products, in particular the cytokines, some of which have been demonstrated to greatly influence luteal PG and progesterone production. Despite the plentitude of investigations, a precise role for PGs other than PGF2 alpha in regulation of CL function is still obscure, mainly lacking evidence of cell-specific expression of various classes of PG receptors and their intracellular signaling mechanisms.
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Affiliation(s)
- J Olofsson
- Department of Obstetrics and Gynaecology, University of British Columbia, Vancouver, Canada
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Tamby JP, Charpigny G, Reinaud P, Martal J. Phospholipase A2 activity in endometrium from early pregnant and non-pregnant ewes. PROSTAGLANDINS 1993; 46:407-15. [PMID: 8278618 DOI: 10.1016/0090-6980(93)90077-k] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
In the ewe, synthesis of the luteolytic factor, prostaglandin F2 alpha, increases from day 13 to the end of the estrous cycle. Availability of free arachidonic acid is usually the rate-limiting step in prostaglandin biosynthesis. Phospholipase A2 (PLA2) may be the key enzyme for the hydrolysis of arachidonic acid from membrane-bound phospholipids. To investigate uterine PLA2 activity during the estrous cycle and early pregnancy, we monitored the release of [14C]oleic acid from the substrate 1-palmitoyl-2-[14C]oleoyl-phosphorylcholine by homogenates and cytosolic fractions of endometrium from ewes on days 12, 14 and 16 of the estrous cycle or pregnancy. We observed that PLA2 activity dropped by 58% (p < 0.02) in day-16 pregnant endometrium compared to day-16 non-pregnant endometrium. We then investigated whether the reduced PLA2 activity was due to induction of a specific inhibitor. The PLA2-inhibitor activity was determined by monitoring the inhibition of release of [14C]oleic acid from the radioactive substrate by porcine pancreatic PLA2. Inhibition by endometrial homogenates of pregnant animals of the control enzyme activity was 27% and only 14% by cyclic ones. Inhibition was dose-dependent and was as high as 53% (p < 0.01) with 1 mg protein from pregnant endometrial homogenates. Endometrial PLA2 behaved as a Michaëlian enzyme in the endometrium of day-16 cyclic ewes (Km = 79.4 mumol/l). Furthermore, the inhibitory activity from pregnant endometrium had characteristics of competitive inhibition. Our results suggest that inhibition of endometrial PLA2 activity could occur in early pregnant ewes.
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Affiliation(s)
- J P Tamby
- Unite d'Endocrinologie de I'Embryon, Station de Physiologie Animale, I.N.R.A., Jouy-en-Josas, France
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Yao K, Wu X, Thompson JE, Carlson JC. Isolation and characterization of deteriosomes from rat liver. J Cell Biochem 1993; 51:488-94. [PMID: 8496249 DOI: 10.1002/jcb.2400510414] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Deteriosomes, a new class of microvesicles, have been isolated from rat liver tissue. These microvesicles are similar to those isolated previously from plant tissue [Yao et al., Proc Natl Acad Sci USA 88:2269-2273, 1991] in that they are nonsedimentable and enriched in membrane catabolites, particularly products of phospholipid degradation. Liver deteriosomes range in size from 0.05 microns to 0.11 microns in radius. They are also much more permeable than microsomal membrane vesicles indicating that the deteriosome bilayer is perturbed. The data are consistent with the proposal that deteriosomes are formed from membranes by microvesiculation and that they represent an intermediate stage of membrane deterioration. Furthermore, liver deteriosomes were found to contain phospholipase A2 activity. This suggests that they not only serve as a means of moving destabilizing macromolecular catabolites out of membranes into the cytosol but also possess enzymatic activity. The fact that the specific activity of phospholipase A2 is higher in deteriosomes than in deteriosome-free cytosol suggests that some of the enzymatic activity traditionally assumed to be cytosolic may in fact be associated with deteriosomes.
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Affiliation(s)
- K Yao
- Department of Biology, University of Waterloo, Ontario, Canada
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Boone DL, Currie WD, Leung PC. Arachidonic acid and cell signalling in the ovary and placenta. Prostaglandins Leukot Essent Fatty Acids 1993; 48:79-87. [PMID: 8424126 DOI: 10.1016/0952-3278(93)90013-m] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Arachidonic acid (AA) and its metabolites make up a diverse group of signalling molecules important to mediation of metabolic and endocrine function of ovarian and placental cell membranes. This paper reviews recent literature examining AA and eicosanoid involvement in the functional dynamics of follicular development, ovulation and corpus luteum function. The putative roles of AA metabolites in establishment and maintenance of pregnancy are reviewed with reference to decidualization, trophoblast invasion and implantation, maintenance of perfusion of the feto-placental unit and lipid transfer. Finally, recent evidence implicating AA metabolism in mediation of enzyme activity following hormone-receptor coupling within various cells types comprising the placental membranes is reviewed.
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Affiliation(s)
- D L Boone
- University of British Columbia, Obstetrics and Gynecology, Vancouver, Canada
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