Cervical dilatation with prostaglandin analogues prior to vaginal termination of first trimester pregnancy in nulliparous patients.

Dilatation of the cervix with prostaglandin analogues prior to vaginal termination of pregnancy was attempted in 125 nulliparous women in the first trimester of pregnancy. The patients were divided into five groups (25 in each group) and given a single extra-amniotic dose of one of the following prostaglandin analogues 14-16 hours prior to the evacuation of the uterus by vacuum aspiration. (Group A) 15 (S) 15 methyl PGE2 (free acid); (Group B) 15 (S) 15 methyl PGE2 methyl ester; (Group C) 15 (S) 15 methyl PGF2alpha (free acid); (Group D) 15 (S) 15 methyl PGF2alpha methyl ester and(Group E) a mixture of 15 (S) 15 methyl PGE2methyl ester and 15 (S) 15 methyl PGF2alpha methyl ester. Evacuation of the uterus without mechanical dilatation of the cervix was possible in 111 (90%) of the patients. In an additional 10 patients (8%) there was some degree of cervical dilatation and further mechanical dilatation could be performed easily. With the combination of 15 (S) 15 methyl PGE2 methyl ester and 15 (S) 15 methyl PGF2alpha methyl ester the incidence of gastrointestinal side effects and pyrexia were considerably reduced.     

Differential production of prostaglandins within the human uterus

The ability of broken cell preparations of human endometrium, myometrium and a mixture of endometrium and myometrium to convert 14C arachidonic acid to prostaglandins (PG's) was compared. Endometrium metabolished arachidonic acid predominantly to a mixture of PGF2 alpha and PGE2. A similar weight of myometrium showed relatively little activity, the major product identified was 6 oxo PGF1 alpha. However, a combination of endometrium and myometrium showed an enhanced conversion of arachidonic acid to 6 oxo PGF1 alpha associated with a decreased production of PGF2 alpha and PGE2. This suggests that human endometrium and myometrium differ in their ability to metabolize arachidonic acid and in their ability to convert the endoperoxides formed, to PG's.     

Bioconversion of arachidonic acid to prostaglandins and related compounds in human myometrium and uterine cervix

Arachidonic Acid metabolites in human myometrium and uterine cervix were studied using silicic acid column chromatography, thin layer chromatography, reversed phase partition chromatography and gas-liquid chromatography. Myometrium produced 6-ketoPGF1 alpha, PGF2 alpha, PGE2, thromboxane B2. Uterine cervix produced 6-ketoPGF1 alpha, PGF2 alpha, PGE2, thromboxane B2, and one hydroxyacid. There was no difference between the rate of conversion of prostaglandins in myometrium and cervix. But only cervix could convert arachidonic acid to hydroxyacid.     

Effect of bacterial cell wall and lipopolysaccharide on arachidonic acid metabolism by caruncular and allantochorionic tissues from cows that calved normally and those that retained fetal membranes

Immunoactive eicosanoids may have a role in both placental separation and uterine involution in cattle. In the present study, we examined the effects of bacterial cell wall preparation and endotoxins on in vitro prostaglandin synthesis and arachidonic acid (AA) metabolism by caruncular and allantochorionic tissues. Placentomes were obtained about 6 h post partum from cows that delivered normally (n = 10) or those with retained fetal membranes (n = 4); the tissue explants were incubated for 6 h in the presence of labeled or nonlabeled AA. Prostaglandin F(2alpha) (PGF(2alpha)) and E(2) (PGE(2)) were measured by radioimmunoassay, and labeled AA metabolites were separated by reverse phase-high pressure-liquid chromatography. There was no effect of bacterial cell wall preparations or endotoxins on in vitro caruncular PGF(2alpha) secretion. However, bacterial products increased caruncular PGE(2) secretion in both cows that delivered normally and those with retained fetal membranes. For normal delivery cows caruncular tissue, bacterial product also increased leukotriene B(4) (LTB(4)) and decreased both thromboxane B(2) (TXB(2)) and hydroxy-eicosatetranoic acids (HETE) in vitro secretion. For the allantochorion, bacterial products increased in vitro PGF(2alpha) secretion only in cows that delivered normally and increased PGE(2) secretion essentially in cows with retained fetal membranes. In general, 6 keto PGF(1alpha) was the main metabolite secreted by both allantochorionic and carucular tissues. However, in cows with retained fetal membranes, PGE(2) became the most important metabolite secreted by allantochorion, especially in the presence of endotoxin. In conclusion, these results suggest that bacteria found in the early postpartum uterus or their endotoxin affect primarily caruncular and allantochorionic PGE(2) synthesis.     

A radioimmunoassay for 6-keto-prostaglandin F1alpha

A radioimmunoassay for 6-keto-prostaglandin F1alpha has been developed. The assay is accurate and sensitive but since the antiserum cross-reacts 5-10% with prostaglandins (PGs) of the E and F series, solvent extraction and thin layer chromatography are required for absolute specificity. The assay has been validated by comparison with a radiochemical assay and by the use of an inhibitor of 6-keto PGF1alpha formation, 15-hydroperoxy arachidonic acid. 6-Keto PGF1alpha was found to have a low cross reaction with antisera directed against PGE2, PGF2alpha and thromboxane B2.     

Bioconversion of arachidonic acid by human uterine cervical tissue and endocervix in late pregnancy

Prostaglandins (PGs) may play an important role on cervical ripening in late pregnancy, namely cervical dilatation and softening. To investigate this, arachidonic acid metabolites of cervical tissue and endocervix were studied. To separate and identify the metabolites, silicic acid chromatography, thin layer chromatography, reversed phase chromatography, gas-liquid chromatography and GC-MS were used. In cervical tissue, arachidonic acid was converted to 6-ketoPGF1 alpha, PGF2 alpha, PGE2, thromboxane B2, and 12-HETE. In endocervix, arachidonic acid was converted to PGF2 alpha, PGE2, thromboxane B2, 12-hydroxy-5, 8, 10-heptadecatrienoic acid, and 12-HETE. There was no relation between the arachidonic acid conversion rate and the Bishop score (points of cervical ripening).     

Phytoestrogens modulate prostaglandin production in bovine endometrium: cell type specificity and intracellular mechanisms

Prostaglandins (PGs) are known to modulate the proper cyclicity of bovine reproductive organs. The main luteolytic agent in ruminants is PGF2alpha, whereas PGE2 has luteotropic actions. Estradiol 17beta (E2) regulates uterus function by influencing PG synthesis. Phytoestrogens structurally resemble E2 and possess estrogenic activity; therefore, they may mimic the effects of E2 on PG synthesis and influence the reproductive system. Using a cell-culture system of bovine epithelial and stromal cells, we determined cell-specific effects of phytoestrogens (i.e., daidzein, genistein), their metabolites (i.e., equol and para-ethyl-phenol, respectively), and E2 on PGF2alpha and PGE2 synthesis and examined the intracellular mechanisms of their actions. Both PGs produced by stromal and epithelial cells were significantly stimulated by phytoestrogens and their metabolites. However, PGF2alpha synthesis by both kinds of cells was greater stimulated than PGE2 synthesis. Moreover, epithelial cells treated with phytoestrogens synthesized more PGF2alpha than stromal cells, increasing the PGF2alpha to PGE2 ratio. The epithelial and stromal cells were preincubated with an estrogen-receptor (ER) antagonist (i.e., ICI), a translation inhibitor (i.e., actinomycin D), a protein kinase A inhibitor (i.e., staurosporin), and a phospholipase C inhibitor (i.e., U73122) for 0.5 hrs and then stimulated with equol, para-ethyl-phenol, or E2. Although the action of E2 on PGF2alpha synthesis was blocked by all reagents, the stimulatory effect of phytoestrogens was blocked only by ICI and actinomycin D in both cell types. Moreover, in contrast to E2 action, phytoestrogens did not cause intracellular calcium mobilization in either epithelial or stromal cells. Phytoestrogens stimulate both PGF2alpha and PGE2 in both cell types of bovine endometrium via an ER-dependent genomic pathway. However, because phytoestrogens preferentially stimulated PGF2alpha synthesis in epithelial cells of bovine endometrium, they may disrupt uterus function by altering the PGF2alpha to PGE2 ratio.     

Prostaglandin synthesis in rat adrenocortical cells.

The biosynthesis of prostaglandins by isolated rat adrenocortical cells has been studied by determinations of products formed during incubations with labeled arachidonic acid and by radioimmunoassays. Analysis by thin-layer chromatographic separation of silicic acid column fractions indicated that PGE2, PGA2, (B2) and PGF2 alpha were the predominant prostaglandins formed by rat adrenocortical cells. Approximately 75% of the incorporated isotope was associated with the prostaglandins of the PGE pathway [PGE2 + PGA2 (B2)]. This was a consistent finding whether cells were incubated directly with arachidonic acid or with cells prelabeled with the substrate prior to study. ACTH did not affect the uptake or oxidation of [1-14C]-arachidonate, but did significantly increase incorporation of labeled substrate into [14C]prostaglandins. Of the ACTH-induced increase, 92% was accounted for by an increase in prostaglandins of the E pathway. Studies with prelabeled cells indicated that 77% of the prostaglandins synthesized in both control and ACTH-stimulated adrenocortical cells was released into the incubation medium during the 2-hr study. These had the same composition [88% PGE2 + PGA2 (B2)] as did the intracellular prostaglandins. Analysis by radioimmunoassays gave comparable data on the distribution of E- and F-type prostaglandins in control cells and cells incubated with ACTH or dibutyryl cyclic AMP. Thus, with these techniques, 88-92% of the increased prostaglandin synthesis due to ACTH or cyclic AMP was produced by the PGE2 rather than the PGF2 alpha pathway.     

Effect of prostaglandins against alloxan-induced diabetes mellitus

Previously, we observed that alloxan-induced in vitro cytotoxicity and apoptosis in an insulin secreting rat insulinoma, RIN, cells was prevented by prior exposure to prostaglandin (PG) E(1), PGE(2), PGI(2), PGF(1)(alpha), and PGF(3)(alpha) (P<0.05 compared to alloxan), whereas thromboxane B(2) (TXB(2)) and 6-keto-PGF(1)(alpha) were ineffective. In an extension of these studies, we now report that prior intraperitoneal administration of PGE(1), PGE(2), PGF(1)(alpha), and PGF(3)(alpha) prevented alloxan-induced diabetes mellitus in male Wistar rats, whereas PGI(2), TXB(2), and 6-keto PGF(1)(alpha) were not that effective. PGE(1), PGE(2), PGF(1)(alpha), and PGF(3)(alpha) not only attenuated chemical-induced diabetes mellitus but also restored the antioxidant status to normal range in red blood cells and pancreas. These results suggest that PGE(1), PGE(2), PGF(1)(alpha), and PGF(3)(alpha) can abrogate chemically induced diabetes mellitus in experimental animals and attenuate the oxidant stress that occurs in diabetes mellitus.     

Prostaglandin (PG) analysis in urine of humans and rats by different radioimmunoassays: effect on PG-excretion by PG-synthetase inhibitors, laparotomy and furosemide.

The radioimmunological (RIA) determination of prostaglandin (PG) E2 and of PGF2alpha in urine of humans and rats is described in detail. After extraction and chromatography PGE2 was determined by using a PGE specific antibody or by using either PGB or PGF2alpha specific antibodies after the respective conversion procedures. The three different RIA procedures were compared to each other. PGF2alpha was determined by a specific antibody to PGF2alpha. Basal excretion of PGE2 and of PGF2alpha in healthy women on free diet was 9.3 ng/hour+/-0.98 and 18.3 ng/hour +/- 2.5 respectively. Furosemide increased the excretion of PGE2 and of PGF2alpha in humans significantly, while PG-excretion rates decreased on indomethacin. In rat urine PGE2 and PGF2alpha increased markedly from 46.2 pg/min +/- 9.3 and 27+/- 3.4 to 253.8 +/- 43.3 and 108 +/- 12.6 pg/min (per one kidney) in the anesthetized-laparotomized animal. This increase was abolished after giving two different PG synthetase inhibitors.     

Evolution of Streptozotocin–Pancreatic Damage in the Rat: Modulatory Effect of Endothelins on the Nitridergic and Prostanoid Pathway

Many lines of evidence indicate that an increased pancreatic production of nitric oxide (NO) and prostaglandins (PGs) is found in the pancreas of streptozotocin-diabetic rats and that endothelins (ETs) are closely related to the nitridergic and prostanoid pathway in several tissues. In the present study the relationship between NO, ETs, and PGs has been explored in isolated pancreatic tissue from streptozotocin-diabetic rats. Pancreatic ET levels are higher in pancreatic tissues from diabetic (D) rats compared to control (C) animals. The addition of nitric oxide synthase (NOS) inhibitors (1 mM N(G)-nitro-l-arginine methyl ester, 600 microM N(G)-monomethyl-l-arginine) in the incubating medium reduces and NO donors (SIN-1, 300 microM spermine suppress, NONOate 100 microM) increases ET levels in pancreatic slices from C and D animals. PGE(2) (10(-7) M) increases and indomethacin (10(-6) M) decreases ET pancreatic production only in D but not in C tissues when added into the incubating bath. When tissues are incubated in the presence of endothelin 1 (ET-1) (10(-7) M), NOS activity is higher in C pancreas, while the ET-receptor antagonist bosentan (B) decreases NOS levels in D but not in C tissues. When pancreatic arachidonic acid (AA) conversion to prostaglandins was explored, ET-1 increased PGF(2alpha), PGE(2), and TXB(2) levels in C but not in D tissues. B abolishes TXB(2) increment due to the diabetic state, but failed in modulating AA conversion to 6-keto PGF(1alpha), PGF2(alpha) and PGE(2) in D pancreas. Our results show an alteration in AA metabolism, ET production, and NO increment associated with pancreatic damage due to streptozotocin.     

Effective use of rabbit gastric antral mucosal slices in prostaglandin synthesis and metabolism studies

Intact slice preparations of rabbit stomach (antral mucosa, corporal mucosa, antral muscle and corporal muscle) were incubated and the released prostaglandins (PGs) were measured by reverse-phase high-performance liquid chromatography using 9-anthryldiazomethane for derivatization. With respect to total PG production, the highest amounts were generated by antral mucosal slices. Antral mucosal slices produced PGE2, 6-keto PGF1 alpha, thromboxane B2, PGF2 alpha and PGD2 (in descending order of magnitude) and possessed a high capacity for producing 13,14-dihydro-15-keto derivatives of both PGE2 and PGF2 alpha. Studies utilizing aspirin, EGTA or Ca2+ revealed that PG release by antral mucosal slices in the present in vitro system reflects a composite of the activities of phospholipase A3, PG cyclooxygenase and PG-metabolizing enzymes. These results show that antral mucosal slices will be useful in physiological and pharmacological studies on PG synthesis and metabolism of the stomach.     

What regulates placental steroidogenesis in 90-day pregnant ewes?

By day-90, the placenta secretes half of the circulating progesterone and 85% of the circulating estradiol-17beta [Weems YS, Vincent D, Tanaka Y, et al. Effects of prostaglandin F(2alpha) on sources of progesterone and pregnancy in intact, ovariectomized, and hysterectomized 90-100 day pregnant ewes. Prostaglandins 1992;43:203-22; Weems YS, Vincent DL, Nusser K, et al. Effects of prostaglandin F(2alpha) (PGF(2alpha)) on secretion of estradiol-17beta and cortisol in 90-100 day hysterectomized, intact, or ovariectomized pregnant ewes. Prostaglandins 1994;48:139-57]. Ovariectomy (OVX) or prostaglandin (PG) F(2alpha) (PGF(2alpha)) does not abort intact or OVX 90-day pregnant ewes and PGF(2alpha) regresses the corpus luteum, but does not affect placental progesterone secretion in vivo [Weems YS, Vincent D, Tanaka Y, et al. Effects of prostaglandin F(2alpha) on sources of progesterone and pregnancy in intact, ovariectomized, and hysterectomized 90-100 day pregnant ewes. Prostaglandins 1992;43:203-22]. Luteal progesterone secretion in vitro at day-90 of pregnancy in ewes is regulated by PGE(1)and/or PGE(2), not by ovine luteinizing hormone (LH; 3). Concentrations of PGE in uterine or ovarian venous plasma averaged 6 ng/ml at 90-100 days of pregnancy in ewes [Weems YS, Vincent DL, Tanaka Y, Nusser K, Ledgerwood KS, Weems CW. Effect of prostaglandin F(2alpha) on uterine or ovarian secretion of prostaglandins E and F(2alpha) (PGE; PGF(2alpha)) in vivo in 90-100 day hysterectomized, intact or ovariectomized pregnant ewes. Prostaglandins. 1993;46:277-96]. Ovine placental PGE secretion is regulated by LH up to day-50 and by pregnancy specific protein B (PSPB) after day-50 of pregnancy [Weems YS, Kim L, Humphreys V, Tsuda V, Weems CW. Effect of luteinizing hormone (LH), pregnancy specific protein B (PSPB), or arachidonic acid (AA) on ovine endometrium of the estrous cycle or placental secretion of prostaglandins E(2) (PGE(2)) and F(2alpha) (PGF(2alpha)), and progesterone in vitro. Prostaglandins Other Lipid Mediators 2003;71:55-73]. Indomethacin (INDO), a prostaglandin synthesis inhibitor [Lands WEM. The biosynthesis and metabolism of prostaglandins. Annu Rev Physiol 1979;41:633-46], lowers jugular venous progesterone [Bridges PJ, Weems YS, Kim L, et al. Effect of prostaglandin F(2alpha) (PGF(2alpha)), indomethacin, tamoxifen or estradiol-17beta on pregnancy, progesterone and pregnancy specific protein B (PSPB) secretion in 88-90 day pregnant ewes. Prostaglandins Other Lipid Mediators 1999;58:113-24] and inferior vena cava PGE of pregnant ewes with ovaries by half at day-90 [Bridges PJ, Weems YS, Kim L, LeaMaster BR, Vincent DL, Weems CW. Effect of prostaglandin F(2alpha) (PGF(2alpha)), indomethacin, tamoxifen or estradiol-17beta on prostaglandin E (PGE), PGF(2alpha) and estradiol-17beta secretion in 88-90 day pregnant sheep. Prostaglandins Other Lipid Mediators 1999;58:167-78]. In addition, treatment of 90 day ovine diced placental slices with androstenedione in vitro increased placental estradiol-17beta, but treatment with PGF(2alpha)in vitro did not decrease placental progesterone secretion, which indicates that ovine placenta progesterone secretion is resistant to the luteolytic action of PGF(2alpha) [Weems YS, Bridges PJ, LeaMaster BR, Sasser RG, Vincent DL, Weems CW. Secretion of progesterone, estradiol-17beta, prostaglandins (PG) E (PGE), F(2alpha) (PGF(2alpha)), and pregnancy specific protein B (PSPB) by day 90 intact or ovariectomized pregnant ewes. Prostaglandins Other Lipid Mediators 1999;58:139-48]. This also explains why ovine uterine secretion of decreased around day-50 [Weems YS, Kim L, Humphreys V, Tsuda V, Weems CW. Effect of luteinizing hormone (LH), pregnancy specific protein B (PSPB), or arachidonic acid (AA) on ovine endometrium of the estrous cycle or placental secretion of prostaglandins E(2) (PGE(2)) and F(2alpha) (PGF(2alpha)), and progesterone in vitro. Prostaglandins Other Lipid Mediators 2003;71:55-73], when placental estradiol-17beta secretion is increasing [Weems C, Weems Y, Vincent D. Maternal recognition of pregnancy and maintenance of gestation in sheep. In: Reproduction and animal breeding: advances and strategies. Enne G, Greppi G, Lauria A, editors, Elsevier Pub., Amsterdam 1995. p. 277-93]. Treatment of 90 day pregnant ewes with estradiol-17beta+ PGF(2alpha), but not either treatment alone, caused a linear increase in both estradiol-17beta and PGF(2alpha) and ewes were aborting [Bridges PJ, Weems YS, Kim L, Sasser RG, LeaMaster BR, Vincent DL, Weems CW. Effect of prostaglandin F(2alpha) (PGF(2alpha)), indomethacin, tamoxifen or estradiol-17beta on pregnancy, progesterone and pregnancy specific protein B (PSPB) secretion in 88-90 day pregnant ewes. Prostaglandins Other Lipid Mediators 1999;58:113-24; Bridges PJ, Weems YS, Kim L, LeaMaster BR, Vincent DL, Weems CW. Effect of prostaglandin F(2alpha) (PGF(2alpha)), indomethacin, tamoxifen or estradiol-17beta on prostaglandin E (PGE), PGF(2alpha) and estradiol-17beta secretion in 88-90 day pregnant sheep. Prostaglandins Other Lipid Mediators 1999;58:167-78]. Pregnant ewes OVX on day 83 of pregnancy and placental slices cultured in vitro secretes 2-3-fold more estradiol-17beta, PSPB, PGE, and progesterone than placental slices from 90 day intact pregnant ewes, but placental PGF(2alpha) secretion by placental slices from intact or OVX ewes did not change [Denamur R, Kann G, Short R V. How does the corpus luteum of the sheep know that there is an embryo in the uterus? In: Pierrepont G, editor. Endocrinology of pregnancy and parturition, vol. 2. Cardiff, Wales, UK: Alpha Omega Pub Co.; 1973. p. 4-38]. The objective of these experiments was to determine what regulates ovine placental progesterone and estradiol-17beta secretion at day-90 of pregnancy, since the hypophysis [Casida LE, Warwick J. The necessity of the corpus luteum for maintenance of pregnancy in the ewe. J Anim Sci 1945;4:34-9] or ovaries [Weems CW, Weems YS, Randel RD. Prostaglandins and reproduction in female farm animals. Vet J 2006;171:206-28] are not necessary after day-55 to maintain pregnancy. In Experiment 1, diced placental slices from day-90 intact or OVX pregnant ewes that were ovariectomized or laparotomized and ovaries were not removed on day 83 were collected on day-90 and incubated in vitro in M-199 with Vehicle, ovine luteinizing hormone (oLH), ovine follicle stimulating hormone (oFSH), ovine placental lactogen (oPL), PGE(l), PGE(2), PGD(2), PGI(2), insulin-like growth factor (IGF) 1 or 2 (IGF(l); IGF(2)), leukotriene C(4) (LTC(4)), platelet activating factor (PAF) 16 or 18 (PAF-16; PAF-18) at doses of 0, 1, 10, or 100ng/ml for 4h. In Experiment 2, placental slices from day-90 intact and OVX (intact or OVX laporotomized 7 days earlier) pregnant ewes were incubated in vitro with vehicle, INDO, Meclofenamate (MECLO), PGE(l), PGE(2), INDO+PGE(1), MECLO+PGE(l), INDO+PGE(2), or MECLO+PGE(2) for 4h. Media were analyzed for progesterone, estradiol-17beta, PGE, or PGF(2alpha) by RIA. Hormone data in media were analyzed in Experiment 1 by a 2x3x13 and in Experiment 2 by a 2x9 Factorial Design for ANOVA. In Experiment 1, placental progesterone, PGE, or estradiol-17beta secretion were increased (P< or =0.05) two-fold by OVX. Progesterone was not increased (P> or =0.05) by any treatment other than OVX and only FSH increased (P< or =0.05) estradiol-17beta secretion by placental slices in both OVX and intact ewes 90-day pregnant ewes. In Experiment 2, INDO or MECLO decreased (P< or =0.05) placental progesterone secretion by 88% but did not decrease (P> or =0.05) placental estradiol-17beta secretion from intact or OVX ewes. PGE(l) or PGE(2) increased (P< or =0.05) progesterone secretion only in ewes treated with INDO or MECLO. It is concluded that FSH probably regulates day-90 ovine placental estradiol-17beta secretion, while PGE(l) or PGE(2) regulates day-90 placental progesterone secretion.     

Prostaglandin F2 alpha stimulates phosphatidylinositol turnover and increases the cellular content of 1,2-diacylglycerol in confluent resting Swiss 3T3 cells

Prostaglandin F2 alpha (PGF2 alpha); which stimulates DNA synthesis in resting 3T3 cells, also stimulates the incorporation of [32P]PO4 into phosphatidylinositol. The effect is selective for PGF2 alpha when compared with PGE1, PGE2, and PGF2 beta. Epidermal growth factor (EGF) also stimulates DNA synthesis but does not affect phosphatidylinositol turnover. PGE1, which acts synergistically with PGF2 alpha to enhance DNA synthesis, does not affect the ability of PGF2 alpha, to enhance the incorporation of [32P]PO4 into phosphatidylinositol. PGF2 alpha, also causes a small increase in the cellular content of 1,2-diacylglycerol. This effect is not shared by EGF or PGE1. Stimulation of phosphatidylinositol metabolism resulting in an increase in the cellular content of 1,2-diacylglycerol may thus constitute an event in the pathway leading to the initiation of DNA synthesis in which PGF2 alpha differs in its action from EGF.     

Detrimental effects of prostaglandin F2alpha on preimplantation bovine embryos

Two studies were performed to determine effects of prostaglandin F2alpha (PGF2alpha) on continued development of pre-compacted (in vitro-produced) and compacted (in vivo-derived) bovine embryos. In Experiment 1, pre-compacted embryos were placed in KSOM media supplemented with polyvinyl alcohol (0.3%) and assigned to the following treatments: (1) control; (2) PGF-1 (1 ng/mL PGF2alpha); (3) PGF-10 (10 ng/mL PGF2alpha); (4) PGF-100 (l00 ng/mL PGF2alpha); or (5) PGE-5 (5 ng/mL PGE2). Following 4 days of incubation in assigned treatments, continued development of pre-compacted embryos to blastocysts was reduced by addition of PGF2alpha in culture medium (P = 0.002). Development did not differ between control and PGE2 treatments (P > 0.10). In Experiment 2, compacted morula' s were placed in KSOM-PVA supplemented media and assigned to one of four treatments: (1) control; (2) PGF-0.1 (0.1 ng/mL PGF2alpha); (3) PGF-1 (1 ng/mL PGF2alpha); and (4) PGF-10 (10 ng/mL PGF2alpha). After 24h in culture, embryos were washed and placed in KSOM-BSA (0.5%) without PGF2alpha for an additional 48 h until assessment for development. Continued development of compacted morula to blastocyst was not affected by addition of PGF2alpha to the culture medium (P > 0.10). However, hatching rates of embryos cultured with PGF2alpha were lower (P = 0.05). In conclusion, it is suggested that PGF2alpha has a direct negative effect on continued embryonic development of pre-compacted and compacted bovine embryos.     

High performance liquid chromatography and UV detection for the separation and quantitation of prostaglandins

A fast and reliable method for the separation and quantitation of arachidonic acid metabolites PGF1 alpha, PGF2 alpha, PGD2, PGE1, PGE2, PGB2, PGA2, 6-keto PGE1, 6-keto PGF1 alpha, TxB2 and 15-keto PGE2 by high-performance liquid chromatography has been developed. Utilizing a single reverse-phase column and a UV spectrophotometer, sensitivity as little as 30 nanograms of each of these prostaglandins can be separated and subsequently detected. Although this study was performed using standards, it is highly promising for future application to biological fluids.     

The prostaglandin synthesis in marine fish thrombocyte

1. Prostaglandin (PG) syntheses from labelled highly unsaturated fatty acids were investigated in washed thrombocyte suspensions of four species of marine fish, flounder (Paralichthys olivaceus), black seabream (Acanthopagrus schlegeli), black rockfish (Sebastes schlegeli), and red seabream (Pagrus major). 2. Synthesized PGs were analyzed by thin-layer radiochromatogram scanner and high-performance liquid chromatography. 3. When [1-(14)C]arachidonic acid (AA) was incubated with washer thrombocyte suspension, AA was mainly converted to PGF(2alpha), PGE2, and PGD2 in all species. 4. It was suggested that [1-(14)C]eicosapentaenoic acid was mainly converted in PGs only in black rockfish thrombocytes, and the metabolites were mainly PGE3 and PGD3. 5 However, [1-(14)C]docosahexaenoic acid was not cyclized into PGs in all the species.     

Isozyme specificity of rat liver glutathione S-transferases in the formation of PGF2 alpha and PGE2 from PGH2

When prostaglandin H2 (PGH2) was incubated with a mixture of glutathione S-transferases (GSTs) obtained from S-hexylglutathione affinity chromatography, as much as 40% of it was transformed into a prostanoid whose Rf value corresponded to that of the standard PGF2 alpha. The reaction product was identified as PGF2 alpha by cochromatography with a standard on TLC and HPLC. The stereochemistry of the hydroxyl groups on C-9 and C-11 of the cyclopentane ring was confirmed by mass-spectral analysis of the butylboronate derivative of the reaction product. Neither PGE2 nor PGD2 could substitute for PGH2 in the reaction mixture, indicating that the mechanism of formation of PGF2 alpha is a direct two-electron reduction of the endoperoxide moiety and not through a reduction of the keto group on PGE2 or PGD2. Individual GST isozymes exhibited distinct differences in their catalytic rates of formation of PGF2 alpha from PGH2. Among various GSTs, isozyme IV, a homodimer of Ya size subunit showed the highest activity with a Vmax value of approximately 6000 nmol.min-1.mg-1. In general, the isozymes containing Ya and Yc subunits exhibited relatively high activity toward PGH2, indicating that it is the non-selenium-dependent glutathione peroxidase activity associated with the GSTs that might be responsible for the reduction of PGH2 to PGF2 alpha. Interestingly, isozyme IV also exhibited the highest PGE2 forming activity with a Vmax value of approximately 3000 nmol.min-1.mg-1 followed by isozyme I, a homodimer of Yb subunit, which had a Vmax value of 420 nmol.min-1.mg-1. Based on these results, it appears that the GSTs play an important role in the biosynthesis of classical PGs. Therefore, it is conceivable that the tissue-specific formation of PGF2 alpha and PGE2 might, in part, be due to the relative distribution of these enzyme activities in a given tissue. Our results have not only confirmed the previously published reports (E. Christ-Hazelhof et al. (1976) Biochim. Biophys. Acta 450, 450-461), but also have characterized the specificity of GST isozymes in the formation of PGF2 alpha.     

Decreased prostaglandin synthesis in postmortem cerebral cortex from patients with Alzheimer's disease.

The syntheses of prostaglandin (PG) F2 alpha, E2 and D2, and thromboxane (TX) B2 from [14C]arachidonic acid were studied in frontal cortex of human control and Alzheimer's disease (AD) brains using the microsomal fractions. Under the assay conditions employed, it was found that the major metabolite of [14C]arachidonic acid was PGE2 accounting for 63% of total prostanoid production; PGF2 alpha accounted for 21.5%, TXB2 for 9%, and PGD2 for 6.5%. When AD samples were compared to control samples, microsomal PG synthesis was significantly decreased, with reduced production of PGE2, PGF2 alpha and PGD2. Such decreases in AD brain seem unrelated to age, sex, postmortem delay and, as far as could be determined, antemortem state. In both control and Alzheimer groups, a history of anti-inflammatory therapy seemed to correlate with increased PG synthesis.     

Epinephrine stimulates prostaglandin synthesis by bullfrog lung from warm-acclimated, but not cold-acclimated, animals

Exogenous prostaglandins (PGs) have been shown to have differing effects on frog lung contractility. In this study, prostaglandin synthesis was measured in lung tissues from warm-acclimated (WA, 22 degrees C) and cold-acclimated (CA, 5 degrees C) American bullfrogs, Rana catesbeiana, incubated for 30 min at 5 degrees or 22 degrees C. Media were assayed by radioimmunoassay for PGE2, PGF2 alpha, 6-keto PGF 1 alpha (the metabolite of PGI2), and thromboxane (TX)B2 (the metabolite of TXA2). PGE2 was produced in greatest quantity by tissues from WA and CA animals, at both incubation temperatures. Epinephrine stimulated PGE2, PGF2 alpha, and TXB2 synthesis at 22 degrees C but only stimulated PGE2 production at 5 degrees C. In tissues from CA frogs, epinephrine did not stimulate prostaglandin synthesis at either incubation temperature. Ibuprofen (10(-5) M) inhibited basal and epinephrine-stimulated prostaglandin synthesis in tissues from WA frogs incubated at 22 degrees C. The beta receptor antagonist propranolol (10(-6) M) blocked the epinephrine-stimulated synthesis of PGE2, PGF2 alpha and TXB2, suggesting epinephrine stimulates prostaglandin synthesis through beta receptor activation. The absence of stimulation by epinephrine in lung from CA animals, but not in 5 degrees C incubations of tissues from WA animals, suggests that a modification of beta receptors occurs during prolonged cold exposure.