Eicosanoids production in endometriosis

In order to investigate the production of eicosanoids in human endometrium, myometrium, leiomyoma, adenomyosis, normal ovary, non-endometrial cyst and endometrial cyst, slices of each tissue were incubated. 6-Keto-prostaglandin (PG) F1 alpha, thromboxane (TX) B2, PGF2 alpha and PGE2 concentrations in the incubation medium were measured by direct RIA. 6-Keto-PGF1 alpha production of adenomyosis was significantly higher than that of endometrium, myometrium and leiomyoma, especially in the menstrual phase. The production of eicosanoids in endometrial cyst was significantly higher than that of non-endometrial cyst and normal ovary. These results suggest that endometriosis is associated with increased eicosanoid production in vivo.     

Expression of enzymes of cyclooxygenase pathway and secretion of prostaglandin E2 and F2alpha by porcine myometrium during luteolysis and early pregnancy

Past studies of uterine prostaglandin (PGs) and pig reproduction have focused on endometrial rather than myometrial PGs. This study documents the synthesis and secretion of myometrial prostaglandins (PGs) in pigs and the involvement of oxytocin (OT) in these processes. Cyclooxygenase-2 (COX-2) expression was similar in myometrial explants from cyclic and pregnant pigs (days 14-16) and OT (10(-7) M) in vitro significantly increased COX-2 protein regardless of reproductive state. Basal expression of prostaglandin E2 synthase (PGES) was higher during pregnancy than during luteolysis. Conversely, prostaglandin F synthase (PGFS) was highest during luteolysis and lower in myometrium from gravid animals. OT had no influence on the expression of PGES and PGFS. In another tissue culture experiment, myometrial slices produced more PGE2 than PGF2alpha regardless of reproductive state of the female. OT stimulated PGE2 production in myometrium harvested during luteolysis and increased PGF2alpha production in all tissues examined. Progesterone (P4; 10(-5) M) blocked stimulatory effect of OT on myometrial PG release. Myometrial OTr mRNA was higher (P=0.03) during luteolysis than during pregnancy. In conclusion: (1) oxytocin increases myometrial COX-2 expression, but does not influence the expression of terminal enzymes of PGs synthesis (PGES and PGFS); (2) porcine myometrium preferentially produces PGs during early pregnancy and secretes more PGE2 than PGF2alpha; (3) myometrial OT and OTr support secretion of PGs from myometrium during luteolysis.     

Prostaglandin E2 and F2 alpha in mid-pregnant rat uterus and at parturition

Prostaglandin E2 (PGE2) and F2 alpha (PGF2 alpha) produced by 15 days pregnant rat myometrium, by parturient rat myometrium and myometrium plus endometrium were measured in vitro. The results showed that the PGs produced by parturient myometrium were higher than these obtained during mid-pregnancy. Myometrium with endometrium released more PGs than myometrium alone, and the addition of arachidonic acid (AA) at 10 DM did not show any significant effect. Exogenous progesterone or estradiol-17b at a concentration of 1 Dmol had no effect on parturient uterine PG secretions.     

Endometriosis origin from primordial germ cells

Endometriosis is defined by the presence of endometrial ectopia. Multiple hypotheses have been postulated to explain the etiology of endometriosis to understand various clinical evidences. The etiology of endometriosis is still unclear.The primary question to understanding the etiology of endometrial ectopia (endometriosis) is determining the origin of eutopic (normally cited) endometrium.According to the new theory, primordial germ cells migrate from hypoblast (yolk sac close to the allantois) to the gonadal ridges. The gonadal ridges which composed of primordial germ cells derive to the: eutopic endometrium, ovary, ovarian ligament and ligamentum teres uteri.There are 2 principal processes in uterine organogenesis: the intersection of gonadal ridges with mesonephral ducts to form the uterine folds with an endometrial cavity and the fusion of the both uterine folds together to form the unicavital (normal) uterus. In the uterine folds there are closer cell-to-cell communications, polypotential germ cells differentiate and grow into myometrium and endometrial layers.Some of the polypotential germ cells fail to reach the ridges and stay in the peritoneal cavity, where they may be transforming into external endometrial heterotopies.The main insight in the etiology of endometriosis is polypotential germ cells origin, which may explain its potency, pathogenesis and expansion.     

Conceptus-derived prostaglandins regulate endometrial function in sheep

In sheep, the trophectoderm of the elongating conceptus secretes interferon tau (IFNT) and prostaglandins (PGE2, PGF2alpha, PGI2). The PGs are derived from PG synthase 2 (PTGS2), and inhibition of PTGS2 in utero prevents conceptus elongation. IFNT increases expression of many genes in the endometrial epithelia that regulate conceptus elongation. This study tested the hypothesis that PGs secreted by the conceptus regulate endometrial functions that govern conceptus elongation. Cyclic ewes received intrauterine infusions of control vehicle or early pregnancy levels of IFNT, PGE2, PGF2alpha, or PGI2 from Days 10-14 postestrus. Expression levels of endometrial GRP, IGFBP1, and LGALS15, whose products stimulate trophectoderm cell migration and attachment, were increased by PGE2, PGI2, and IFNT. All PGs and IFNT increased expression of the HEXB protease gene, but only IFNT increased the CST6 protease inhibitor gene. Differential effects of PGs were observed for expression of the CTSL protease gene and its inhibitor, CST3. IFNT, PGF2alpha, and PGI2 increased ANGPTL3 expression, but only IFNT and PGE2 increased HIF1A expression, both of which regulate angiogenesis. For glucose transporters, IFNT and all PGs increased SLC2A1 expression, but only PGs increased SLC2A5 expression, whereas endometrial SLC2A12 and SLC5A1 expression levels were increased by IFNT, PGE2, and PGF2alpha. Infusions of all PGs and IFNT increased the amino acid transporter SLC1A5, but only IFNT increased SLC7A2 expression. In the uterine lumen, only IFNT increased glucose levels, and only PGE2 and PGF2alpha increased total amino acids. These results indicate that PGs and IFNT from the conceptus coordinately regulate endometrial functions important for growth and development of the conceptus during the peri-implantation period of pregnancy.     

Endometrial HSD11B1 and cortisol regeneration in the ovine uterus: effects of pregnancy, interferon tau, and prostaglandins

In ruminants, the elongating conceptus secretes interferon tau (IFNT), the pregnancy recognition signal, and prostaglandins (PGs). Progesterone from the ovary induces prostaglandin synthase two (PTGS2) and hydroxysteroid (11-beta) dehydrogenase 1 (HSD11B1) in the endometrial epithelia, and PTGS2-derived PGs regulate endometrial functions and conceptus elongation. The enzyme HSD11B1 interconverts inactive cortisone and active cortisol. These studies determined the effects of pregnancy, IFNT, and PGs on endometrial HSD11B1 expression and activity in the ovine uterus. Study one found that HSD11B1 activity was present in both the endometrium and conceptus during early pregnancy. In study two, ewes received intrauterine infusions of vehicle as a control (CX) or meloxicam (MEL), a PTGS2 inhibitor, from Days 8 to 14 of pregnancy. Endometrial HSD11B1 activity and cortisol in the uterine lumen were substantially lower in MEL-infused ewes. In study three, cyclic ewes received intrauterine infusions of vehicle as a CX, MEL, recombinant ovine IFNT, or IFNT and MEL. Infusion of IFNT increased endometrial HSD11B1 expression and activity and cortisol in the uterine lumen, and this effect was diminished by coinfusion of MEL. In study four, cyclic ewes were infused with vehicle as a CX, IFNT, PGE2, PGF2 alpha, or PGI2. Infusion of all the PGs and IFNT increased endometrial HSD11B1 expression and activity, and IFNT and PGI2 infusion increased cortisol in the uterine lumen. These studies support the idea that IFNT and PGs from the conceptus regulate endometrial HSD11B1 expression and activity that regenerates bioactive cortisol in the ovine uterus during early pregnancy to influence endometrial functions and conceptus elongation.     

Cyclooxygenase and lipoxygenase pathways in the preimplantation rabbit uterus and blastocyst

We have measured by radioimmunoassay the concentration and production of 5(S)-hydroxy-6,8,11,14-eicosatetraenoic acid (5-HETE), a metabolite in the lipoxygenase pathway, and PGs in different uterine compartments, and blastocysts during the preimplantation period in the rabbit. The production is defined as the synthesis minus the metabolism for a defined period of time. The pattern of uterine PGF production on days 5-6.5 was quite similar for the whole uterus and the myometrium showing a peak production on Day 6. The concentration and production of PGF were always higher in the endometrium. While significant production of PGE was noticed in the whole uterus on days 5-6 and in the myometrium on Day 6, the endometrium showed some production on these days. On the contrary, absolutely no production of this PG was observed in the endometrium on Day 6.5. The concentration and production of 6-keto-PGF1 alpha were always lower in the endometrium than those observed in the myometrium or the whole uterus. While highest production of this PG was found to be on Day 6.5 in the whole uterus and on Day 5 in the endometrium, the production in the myometrium remained constant on all days examined. The production of 5-HETE in the endometrium was noticeable on Days 5-6.5, in the whole uterus on Days 5 and 6.5, and in the myometrium only on Day 6.5. However, the concentrations of 5-HETE showed a tendency to be higher at 2 h than at 0 h in these compartments on Days 5-6.5. Furthermore, a linear increase in 5-HETE levels both at 0 h and 2 h was observed in the endometrium on Days 5-6.5; no such difference in mean 5-HETE level was noted in the whole uterus or myometrium on any of these days. The production of 5-HETE in the blastocyst was noted only on Day 5. The results not only demonstrate the presence of both the cyclooxygenase and the lipoxygenase pathways in the preimplantation rabbit uterus and blastocyst, their differential operation in various compartments of the uterus on various days of early pregnancy suggests an integrated role for these mediators in embryo-uterine interaction during implantation.     

Nitric oxide (NO) inhibits prostaglandin E2 9-ketoreductase (9-KPR) activity in human fetal membranes

Nitric oxide (NO) synthesized by fetal membranes may act either directly inhibiting myometrium contractility or indirectly interacting with tocolytic agents as prostaglandins (PGs). Here we examined if NO could modulate prostaglandin E(2) 9-ketoreductase (9-KPR) activity in human fetal membranes (HFM). 9-KPR is the enzyme that converts PGE(2) into PGF(2alpha), the main PGs known to induce uterine contractility at term. Chorioamnion explants obtained from elective caesareans were incubated with aminoguanidine (AG), an iNOS inhibitor, or NOC-18, a NO donor. NOC-18 (2mM) increased PGE(2) production and diminished PGF(2alpha) synthesis in HFM. AG presented the opposite effect. When we evaluated the activity of 9-KPR by the conversion of [(3)H]-PGE(2) into [(3)H]-PGF(2alpha) and 13,14-dihidro-15-keto prostaglandin F(2alpha) (the PGF(2alpha) metabolite), we found that NOC-18 inhibited 9-KPR activity. Interestingly, AG did not elicit any effect on 9-KPR but l-NAME, a non-selective NOS inhibitor, significantly increased its activity. Our data suggests that exogenous NO inhibits 9-KPR activity in HFM, thus modulating the synthesis of important labor mediators as PGF(2alpha).     

Is protein synthesis necessary for prostaglandin production by guinea-pig endometrium?

The outputs of prostaglandin (PG) F-2 alpha, PGE-2 and 6-keto-PGF-1 alpha from Day-7 and Day-15 guinea-pig endometrium in culture were reduced by the inclusion of actinomycin D, cycloheximide and puromycin in the culture medium, with the output of PGF-2 alpha from Day-15 endometrium being particularly affected during the first 6 h of culture. The intrauterine administration of actinomycin D on Day 10 decreased the outputs of PGF-2 alpha and PGE-2, but not of 6-keto-PGF-1 alpha, from Day-15 endometrium in culture without affecting PG output from Day-15 myometrium in culture. Actinomycin D, cycloheximide and puromycin did not reduce PG output when superfused over the Day-7 and Day-15 guinea-pig uterus in vitro for 20 min, indicating that these compounds do not have a rapid inhibitory effect on endometrial PG synthesis. In fact, they tended to stimulate PG output during this 20-min period, with cycloheximide having a pronounced effect on PGE-2 output. The synthesis of secreted proteins, but not of cellular proteins, was greater by Day-15 than by Day-7 endometrium in culture. Actinomycin D, cycloheximide and puromycin inhibited the synthesis of secreted and cellular proteins by Day-7 and Day-15 endometrium in culture. Protein synthesis and PG synthesis in the endometrium were both inhibited to a greater extent by cycloheximide and puromycin than by actinomycin D. The intrauterine administration of actinomycin D on Day 10 reduced the syntheses of secreted and cellular proteins by Day-15 endometrium in culture. These findings indicate that the endometrial synthesis of PGs, particularly of PGF-2 alpha towards the end of the oestrous cycle, is dependent upon endometrial protein synthesis.     

Changes in prostaglandin production and ovarian function in gilts during endometritis induced by Escherichia coli infection

The aim of this study was to determine the prostaglandins (PGs) production and ovarian function in gilts after intrauterine infusions of 10(6) and 10(9) colony-forming units (cfu)/ml of Escherichia coli (E. coli). In Experiments 1 and 2, 30 ml of saline or 30 ml of E. coli suspension containing 10(6) or 10(9)cfu/ml, were infused once into each uterine horn in three groups of gilts on day 3 of the estrous cycle, respectively. In Experiment 1, 17 days after treatment it was revealed that inoculation of E. coli 10(9)cfu/ml induced severe acute or subacute endometritis while 10(6)cfu of E. coli evoked moderate acute endometritis or resulted in no inflammatory changes. In the gilts receiving 10(9)cfu/ml of E. coli, the concentration of 13,14-dihydro-15-keto-PGF(2)alpha in blood from the jugular vein was elevated (P<0.05-0.001) compared to concentration in the gilts inoculated with 10(6)cfu on days 8-17 after treatment. Both the E. coli-treated groups had a lower (P<0.05, P<0.01) progesterone plasma level from days 10 to 14 after administration than the control group. On day 17 of the study, infusion of E. coli 10(9)cfu/ml, in comparison to 10(6)cfu, resulted in the greater (P<0.001) content of PGE(2) in the myometrium. The content of both PGs in the endometrium as well as PGF(2alpha) in the myometrium of gilts-treated with 10(9)cfu/ml of E. coli was lower (P<0.001) than in gilts-treated with 10(6)cfu of bacteria. Newly formed corpora lutea were found in the gilts infused with 10(6), but not those infused with 10(9)cfu/ml of E. coli on day 17 after infusion. On day 8 of the study (Experiment 2), the blood from utero-ovarian vein of the gilts-treated with 10(9)cfu/ml of bacteria had a higher (P<0.05) PGF(2alpha) level and lower (P<0.001) PGE(2) level than following infusion of E. coli 10(6)cfu/ml. Also on day 8 of the study, the content of PGE(2) in the endometrium, both the PGs in the myometrium as well as cyclooxygenase-2 in the endometrium and myometrium was greater (P<0.01, P<0.001) after applying 10(9)cfu/ml than 10(6)cfu/ml of E. coli. These results indicate that intrauterine infusions of 10(6) or 10(9)cfu/ml of E. coli lead to the development of inflammatory states of different intensities which is connected with different PGF(2alpha) and PGE(2) production and function of ovaries.     

Effects of TAP-144-SR, a sustained-release formulation of a potent GnRH agonist, on experimental endometriosis in the rat

A new, simple experimental endometriosis model was established by auto-transplanting endometrial tissue fragments beneath kidney capsules in female rats. The transplanted endometrial tissue grew well, forming a fluid-filled cyst, which reached maximal size 2 to 3 weeks after transplantation. The growth and maintenance of the transplants was dependent on the ovary: ovariectomy induced regression of well grown transplants. The therapeutic effects of TAP-144-SR (biodegradable microcapsules of copoly (DL-lactic/glycolic acid) copolymer containing a potent GnRH agonist, TAP-144 (D-Leu6-[des-Gly10-NH2]-GnRH ethylamide, leuprolide acetate) were studied with this rat endometriosis model. A single sc injection of TAP-144-SR (corresponding to 1, 10 or 100 micrograms/kg/day of TAP-144), suppressed the growth of the transplanted endometrial tissues and uterine weight in a dose-dependent manner. At 100 micrograms/kg/day, the suppressive effect was more marked in rats given TAP-144-SR than in those given TAP-144 solution. The extent of suppression was comparable to that caused by ovariectomy. Serum and pituitary concentrations of LH and FSH were also reduced more markedly by the administration of TAP-144-SR than by TAP-144 solution. From these results, the present endometriosis model was found to be useful for the evaluation of compounds with potential therapeutic activity. The sustained-release formulation of TAP-144 seems to be beneficial over its solution in terms of both convenience and efficiency for therapy of patients with endometriosis.     

Liquid chromatographic-mass spectrometric determination of cyclooxygenase metabolites of arachidonic acid in cultured cells

A liquid chromatographic-electrospray ionization-mass spectrometric (LC-ESI-MS) technique was developed to simultaneously determine the cyclooxygenase metabolites of arachidonic acid (6-keto-PGF(1alpha), PGD(2), PGE(2), PGF(2alpha), and PGJ(2)) produced by cultured cells. Samples were separated on a C(18) column with water-acetonitrile mobile phase, ionized by electrospray, and detected in the positive mode. Selected ion monitoring (SIM) of m/z 353, 335, 335, 319, and 317 were used for quantifying 6-keto-PGF(1alpha), PGD(2), PGE(2), PGF(2alpha), and PGJ(2), respectively. Prostaglandins were detected at concentrations as low as 1 pg (S/N=3) on the column. The method was used to determine the production of PGs from bovine coronary artery endothelial cells (ECs) and human prostate cancer cells (PC-3) with different degree of invasiveness. Bradykinin (10(-6) M) stimulated a marked increase in the production of 6-keto-PGF(1alpha), PGE(2), and PGF(2alpha) and a small increase of PGD(2) by ECs. 6-Keto-PGF(1alpha) was the major metabolite in these cells. The production of PGE(2) was threefold higher and PGD(2) was twofold higher in PC-3-S (invasive) cells than in PC-3-U (non-invasive) cells.     

Menstrual-PGF2 alpha, PGE2 and TXA2 in normal and dysmenorrheic women and their temporal relationship to dysmenorrhea

Although it has been demonstrated that primary dysmenorrhea is associated with elevated levels of PGF2 alpha in the menstrual fluid, little is actually known of the menstrual-PG profiles of either dysmenorrheic or normal women. In this study, menstrual fluid from normal and dysmenorrheic women was collected from tampons and extracted for PG-like substances. The PGF2 alpha, PGE2 and TXA2 content was analyzed by RIA. This study demonstrates that dysmenorrheics have significantly higher levels/concentrations of menstrual-PGF2 alpha and PGE2 than do normal women, and that there is no difference in the menstrual-PGF2 alpha : PGE2 ratio between the two groups. Also, there is no significant difference in the amount/concentration of menstrual-thromboxane between dysmenorrheic and normal women. Of the parameters considered, the levels/-concentrations of menstrual-PGF2 alpha, PGE2 and TXA2, dysmenorrheic pain correlates best with the rate of menstrual-PGF2 alpha release.     

Progesterone reduces erectile dysfunction in sleep-deprived spontaneously hypertensive rats

Background

The rate-limiting step in prostaglandin (PG) biosynthesis is catalyzed by phospholipase A2 (PLA2) enzymes which hydrolyze arachidonic acid from membrane phospholipids. Despite their importance in uterine PG production, little is known concerning the specific PLA2 enzymes that regulate arachidonic acid liberation in the uterine endometrium. The objectives of this study were to evaluate the expression and activities of calcium-independent Group VI and Group IVC PLA2 (PLA2G6 and PLA2G4C) and calcium-dependent Group IVA PLA2 (PLA2G4A) enzymes in the regulation of bovine uterine endometrial epithelial cell PG production.

Methods

Bovine endometrial epithelial cells in culture were treated with oxytocin, interferon-tau and the PLA2G6 inhibitor bromoenol lactone, alone and in combination. Concentrations of PGF2alpha and PGE2 released into the medium were analyzed. Western blot analysis was performed on cellular protein to determine the effects of treatments on expression of PLA2G4A, PLA2G6 and PLA2G4C. Group-specific PLA2 activity assays were performed on cell lysates following treatment with oxytocin, interferon-tau or vehicle (control), alone and in combination. To further evaluate the role of specific PLA2 enzymes in uterine cell PG biosynthesis, cells were transfected with cDNAs encoding human PLA2G6 and PLA24C, treated as described above and PG assays performed.

Results

Constitutive cell production of PGF2alpha was about two-fold higher than PGE2. Oxytocin stimulated production of both PGs but the increase of PGF2alpha was significantly greater. Interferon-tau diminished oxytocin stimulation of both PGs. The PLA2G6 inhibitor, bromoenol lactone, abolished oxytocin-stimulated production of PGF2alpha. Treatments had little effect on PLA2G4A protein expression. In contrast, oxytocin enhanced expression of PLA2G6 and this effect was diminished in the presence of interferon-tau. Expression of PLA2G4C was barely detectable in control and oxytocin treated cells but it was enhanced in cells treated with interferon-tau. Oxytocin stimulated PLA2 activity in assays designed to evaluate PLA2G6 activity and interferon-tau inhibited this response. In assays designed to measure PLA2G4C activity, only interferon-tau was stimulatory. Cells overexpressing PLA2G6 produced similar quantities of the two PGs and these values were significantly higher than PG production by non-transfected cells. Oxytocin stimulated production of both PGs and this response was inhibited by interferon-tau. Bromoenol lactone inhibited oxtocin stimulation of PGF2alpha production but stimulated PGE2 production, both in the absence and presence of oxytocin. Cells over-expressing PLA2G4C produced more PGE2 than PGF2alpha and interferon-tau stimulated PGE2 production.

Conclusion

Results from these studies indicate that oxytocin stimulation of uterine PGF2alpha production is mediated, at least in part, by up-regulation of PLA2G6 expression and activity. In addition to its known inhibitory effect on oxytocin receptor expression, interferon-tau represses oxytocin-stimulated PLA2G6 expression and activity and this contributes to diminished PGF2alpha production. Furthermore, endometrial cell PGE2 biosynthesis was associated with PLA2G4C expression and activity and interferon-tau was stimulatory to this process.     

The effect of supplementation with n-6 polyunsaturated fatty acids on 1-, 2- and 3-series prostaglandin F production by ovine uterine epithelial cells

Linoleic acid (LA, 18:2n-6) has variously been found to increase or inhibit synthesis of 2-series prostaglandins (PGs), derived from arachidonic acid (AA, 20:4n-6). gamma-linolenic acid (GLA, 18:3n-6) containing oils are promoted to women for a variety of reproductive problems. Little is known concerning their actual effects on reproduction. We investigated the effects of LA, GLA and AA supplementation (25-100 microM) on basal and oxytocin (OT) stimulated production of 1-, 2- and-3 series PGs by uterine epithelial cells isolated from non-pregnant ewes, used as a model system to study endometrial PG production. PGF isomers were measured using radioimmunoassays following separation by high performance chromatography (HPLC). OT challenge increased the proportion of PGF2alpha in relation to PGF1alpha and PGF3alpha in control medium. LA supplementation decreased all PGF isomer production and reduced responsiveness to OT. GLA increased both absolute and proportional PGF1alpha production and slightly enhanced PGF2alpha generation. AA increased PGF2alpha generation and raised its isometric proportion. Both GLA and AA increased overall PGF output significantly but prevented the cells from responding to OT. These results suggest that consumption of LA and GLA are likely to differentially alter both uterine PG metabolism and responsiveness to OT. This may have implications for the control of a variety of reproductive processes.     

Tissue levels of prostaglandins and what do they mean? Studies on the guinea-pig uterus

The ratios of the concentrations of PGF2 alpha, PGE2 and 6-keto-PGF1 alpha in guinea-pig uterine horns, which were removed and placed in ethanol in 1.5 to 2 min, were 0.3:1.0:0.6 on day 7 and 13.8:1.0:0.8 on day 15 of the oestrous cycle. Adding indomethacin (10 micrograms/ml) to the ethanol had no significant effect on the tissue levels observed. These ratios were similar to the ratios of the outputs of PGF2 alpha, PGE2 and 6-keto-PGF1 alpha from the guinea-pig uterus (0.6:1.0:0.9 on day 7 and 7.6:1.0:1.5 on day 15), but were different (particularly on day 7, but only for 6-keto-PGF1 alpha on day 15) to the ratios of the amounts of the three PGs synthesized by homogenates of the guinea-pig uterus (7.2:1.0:2.4 on day 7 and 11.7:1.0:3.3 on day 15). Consequently, the measurement of tissue levels of PGs in the guinea-pig uterus reflects PG synthesis by intact tissue and changes in this synthesis, rather than PG synthesis by homogenates (broken cell preparations). Therefore, it appears meaningful to measure levels of PGs in the guinea-pig uterus since they reflect uterine PG output. Separation of the endometrium from the myometrium, which involved handling and mild trauma, stimulated uterine PG levels, but the ratio of the levels of PGF2 alpha, PGE2 and 6-keto-PGF1 alpha in the endometrium was still similar to that found in the non-separated uterus.     

Role of COX-1 and COX-2 on skin PGs biosynthesis by mechanical scratching in mice

We examined the involvement of cyclooxygenase (COX)-1 and COX-2 on mechanical scratching-induced prostaglandins (PGs) production in the skin of mice. The dorsal regions of mice were scratched using a stainless brush. COXs expressions in the skin were analyzed using real-time PCR and Western blotting. The effect of acetylsalicylic acid (ASA) on the ability of PGs production were determined based on skin PGs level induced by arachidonic acid (AA) application. Mechanical scratching increased PGD2, PGE2, PGI2 and PGF(2 alpha). COX-1 was constitutively expressed and COX-2 expression was enhanced by scratching. Intravenous administration of ASA inhibited PGs biosynthesis in the normal skin. PGs levels of the skin 6h after ASA administration (ASA 6 h) were almost equal to those of the skin 10 min after ASA administration (ASA 10 min). In the scratched skin, AA-induced PGE2 and PGI2 of ASA 6 h were significantly higher than those of ASA 10 min. The skin PGD2 and PGF(2 alpha) of ASA 10 min were almost same to those of ASA 6 h. In the normal skin of COX-1-deficient mice, skin PGD2 level was lower than that of wild-type mice, although PGE2, PGI2 and PGF(2 alpha) levels were almost equal to those of wild type. In the scratched skin of COX-1-deficient mice, PGD2, PGE2, PGI2 and PGF(2 alpha) levels were lower than those of wild-type mice. These results suggested that cutaneous PGD2 could be mainly produced by COX-1, and PGE2 and PGI2 could be produced by COX-1 and COX-2, respectively, in mice.     

Prostacyclin and thromboxane synthesis by endometrial cancer and leiomyomas

To study the role of prostacyclin (PGI2) and thromboxane A2 (TxA2) in uterine tumors, pieces of endometrial cancer (n = 12) and leiomyomas (n = 12) were incubated in vitro, and the productions of 6-keto-prostaglandin F1a (6-keto-PGF1a, a hydration product of PGI2) and thromboxane B2 (TxB2, a hydration product of TxA2), measured by radioimmunoassay, were compared to those of corresponding healthy tissues. The production of 6-keto-PGF1a by endometrial cancer (20.8; 15.1-85.0 ng/mg protein/min, median and interquartile range), by healthy endometrium (25.5; 10.0-55.0), by healthy myometrium (34.9; 25.0-59.9) and by leiomyoma (20.3; 10.2-45.1) was similar. The production of TxB2 was increased by endometrial cancer (55.5; 10.5-155.2, p less than 0.02) in comparison with endometrium (9.8; 4.3-35.1), myometrium (3.8; 2.1-8.0) and leiomyoma (1.9; 1.0-3.8). The 6-keto-PGF1a/TxB2 ratio in endometrial cancer (0.9; 0.3-1.5) was smaller (p less than 0.02) than that in healthy endometrium (3.3; 1.9-4.8). Thus, TxA2 may be a factor in endometrial cancer.     

ENDOMETRIOSIS—A Clinical and Pathological Study of 219 Cases

One hundred twenty-four cases of external endometriosis and 95 cases of adenomyosis were analyzed. The two are clinically different diseases which have one feature in common—a reactive fibrosis to aberrant endometrial tissue. They are coexistent in about the same frequency as would result from a noncausal relationship.The origin of external endometriosis from the epithelial “inclusion” cyst is considered proven histologically. This is the source of origin of most external endometriosis, although occasional involvement from regurgitated endometrium probably occurs. Both the endometrial and the serous cysts have a common parentage in this anlage.Certain histological features that are considered pathognomonic of endometriosis are: (1) the minimal lesion, (2) the characteristic cuboidal lined cyst, (3) the siderophagic cyst without lining, and (4) the siderophagic nest.Recognition of the siderophagic nest will permit identification of extinct endometriosis and thus aid in studies to determine the spontaneous or therapeutically induced regression of the disease.The coexistence of endometriosis with other pelvic pathological changes, notably carcinoma, indicates the need for further studies to search the possibility of relationship.The ability of ectopic deposits of endometrium to become malignant on rare occasions would appear to be proven, but it is a rare occurrence and there is no justification for regarding endometriosis as a premalignant disease.