Detection of Cytosolic Phospholipase A&lt;sub&gt;2&lt;/sub&gt; (cPLA&lt;sub&gt;2&lt;/sub&gt;) in Rat Corpora Lutea: Relationship to Functional Luteolysis

Kurusu, Shiro; Shingaki, Satoshi; Munekata, Yoshiko; Kawaminami, Mitsumori; Hashimoto, Itaru

doi:10.1262/jrd.41.141

Cited by 14 publications

(9 citation statements)

References 22 publications

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“…Although cPLA2 was assumed to be the primary isoform in a pseudopregnant rat CL [5,7], ATK was not so effective in pregnant CLs on either PP0 or PP5 (25 35% inhibition) (Fig. 2).…”

Section: Resultsmentioning

confidence: 99%

“…Plasma progesterone was assayed using a radioimmunoassay as described before [5]. Luteal PGF:~ was determined according to Higuchi et al [16] using a commercial ELISA kit.…”

Section: Assay Of Plasma Progesterone and Luteal Pgf~mentioning

confidence: 99%

“…PLA2, phospholipase A2; PG, prostaglandin; CL, corpus luteum; PRL, prolactin PLA2 activity, mainly exhibited by cPLA2, is shown to increase during functional luteolysis in pseudopregnant rats [5,7]. Mice lacking cPLA2 [8,9] or the FP receptor [10] failed to deliver because of obstructed luteolysis at term.…”

Section: Introductionmentioning

confidence: 99%

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Luteal phospholipase A₂ activity increases during functional and structural luteolysis in pregnant rats

et al. 1999

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We determined eytosolic phospholipase A2 activity of the corpus luteum during luteolysis in pregnant and post-partum rats. Phospholipase A2 activity and its metabolite prostaglandin F2~ 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 Fz~ 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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“…Although cPLA2 was assumed to be the primary isoform in a pseudopregnant rat CL [5,7], ATK was not so effective in pregnant CLs on either PP0 or PP5 (25 35% inhibition) (Fig. 2).…”

Section: Resultsmentioning

confidence: 99%

“…Plasma progesterone was assayed using a radioimmunoassay as described before [5]. Luteal PGF:~ was determined according to Higuchi et al [16] using a commercial ELISA kit.…”

Section: Assay Of Plasma Progesterone and Luteal Pgf~mentioning

confidence: 99%

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Luteal phospholipase A₂ activity increases during functional and structural luteolysis in pregnant rats

et al. 1999

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“…The animals in our study were injected with rather high doses (50IU) of both eCG and hCG, thus exhibiting about three-fold increases in ovulation rates and plasma steroid levels compared to those in immature pseudopregnant rats used elsewhere [12,13,15,16]. eCG would be the determinant for the numbers of ovulated ova and CLs obtained.…”

Section: Discussionmentioning

confidence: 96%

“…PGF2α-induced and spontaneous luteolysis involves increased phospholipase A2 (PLA2) activity [20,29]. We identified 85 kDa cytosolic PLA2 (cPLA2) as the luteal primary isozyme and determined its increasing activity during functional luteolysis in pseudopregnant rats [10,13]. The generation of hydrogen peroxide and LP caused by PGF2α results in the stimulation of PG synthesis through the activation of PLA2 [19,25] and cyclooxygenase [3,8].…”

Section: Discussionmentioning

confidence: 99%

Biphasic Change in Correlation between Ovarian Lipid Peroxides and Progestational Activity during Pseudopregnancy Induced in Immature Rats.

Kurusu

Tsukamoto

Konishi

et al. 1999

The Journal of Veterinary Medical Science

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ABSTRACT. We measured ovarian lipid peroxide (LP) levels and plasma progestins, progesterone (P 4 ) and 20α-dihydroprogesterone, throughout pseudopregnancy in gonadotropin-primed immature rats. Plasma P 4 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 P 4 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.-KEY WORDS: lipid peroxide, progestin, pseudopregnancy, rat.J. Vet. Med. Sci. 61(9): 1039-1042, 1999 Animal and tissue preparation: Immature female rats of the Wistar-Imamichi strain were used in this study. They were kept in an air-and light-conditioned room (temperature, 23 ± 3°C; lights on, 0500-1900 hr). Superovulation and pseudopregnancy were induced by the earlier method [21,22] with a little modification. Twenty six-day-old animals weighing 50-73 g were injected with eCG (50 IU, sc) at 1700 hr followed by hCG (50 IU, ip) 46 hours later. These animals ovulated 34.2 ± 9.0 (mean ± SEM, n=5) ova the next morning. On vaginal smear examination, the rats exhibited proestrus on the 28th, estrus on the 29th day, and diestrus thereafter for 12.9 ± 0.3 (n=24) days. The first diestrous day was designated as day 1 of pseudopregnancy (PSP1) in this report. The rats were killed by decapitation on each day from PSP1 to PSP14 except for PSP2. Systemic blood plasma was kept at 20°C until the steroid assay. Ovaries were kept at 80°C until assay of the LP level.Determination of plasma progestins and ovarian LP: Plasma P4 and 20α-OHP were extracted with n-hexan and isolated by column chromatography. They were then determined in duplicate by radioimmunoassay [6,14,16]. The working range of assays was 12.5-1000 pg for both progestins.LP levels in ovarian homogenates were measured by the thiobarbituric acid test [27]. Values were expressed as nmol of malondialdehyde (MDA) per ovary.Statistical analyses: All data on progestins and LP were expressed as the mean ± SEM (n=6). They were analysed by ANOVA and Student's t-test. Correlation coefficients and, in some cases, the Spearman ranked correlation coefficients of ovarian LP were evaluated with several parameters of luteal progestational activity (P4, 20α-OHP, sum of P4 and 20α-OHP, or the ratio of 20α-OHP to P4). Differences between experimental groups were considered Superoxide radicals (SOR) and other reactive oxygen species have been assumed to play pathological roles in inflammation, cancer and radiation damage. Recent evidence has demonstrated their physiological roles, for example in the regulation of ovarian corpus luteum (CL) function [2,9]. SOR and related...

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Effects of arachidonate metabolism inhibitors on basal and human chorionic gonadotropin-stimulated progesterone secretion by rat corpus luteum cells in vitro

Kurusu

Ohkawa

Kawaminami

2007

Prostaglandins & Other Lipid Mediators

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Detection of Cytosolic Phospholipase A<sub>2</sub> (cPLA<sub>2</sub>) in Rat Corpora Lutea: Relationship to Functional Luteolysis

Cited by 14 publications

References 22 publications

Luteal phospholipase A₂ activity increases during functional and structural luteolysis in pregnant rats

Luteal phospholipase A₂ activity increases during functional and structural luteolysis in pregnant rats

Biphasic Change in Correlation between Ovarian Lipid Peroxides and Progestational Activity during Pseudopregnancy Induced in Immature Rats.

Effects of arachidonate metabolism inhibitors on basal and human chorionic gonadotropin-stimulated progesterone secretion by rat corpus luteum cells in vitro

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Detection of Cytosolic Phospholipase A<sub>2</sub> (cPLA<sub>2</sub>) in Rat Corpora Lutea: Relationship to Functional Luteolysis

Cited by 14 publications

References 22 publications

Luteal phospholipase A2 activity increases during functional and structural luteolysis in pregnant rats

Luteal phospholipase A2 activity increases during functional and structural luteolysis in pregnant rats

Biphasic Change in Correlation between Ovarian Lipid Peroxides and Progestational Activity during Pseudopregnancy Induced in Immature Rats.

Effects of arachidonate metabolism inhibitors on basal and human chorionic gonadotropin-stimulated progesterone secretion by rat corpus luteum cells in vitro

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Luteal phospholipase A₂ activity increases during functional and structural luteolysis in pregnant rats

Luteal phospholipase A₂ activity increases during functional and structural luteolysis in pregnant rats