Effect of exogenous estradiol and progesterone on the uterine tissue levels of prostaglandin F2 (PGF2 ) in ovariectomized mice

Expression of prostaglandin receptors in Chlamydia trachomatis-infected recurrent spontaneous aborters

A study was undertaken to quantify the expression of prostaglandin (PG) receptors and find the effect of gestational age on expression of PG receptor genes in Chlamydia trachomatis-infected recurrent spontaneous aborters (RSA). Endometrial curettage tissue (ECT) was collected from 130 RSA (Group I) and 100 age-matched controls (Group II) at the Department of Obstetrics and Gynecology, Safdarjung Hospital, New Delhi (India). PCR was performed for diagnosis of C. trachomatis cryptic plasmid; mRNA expression of PG receptor genes was assessed by real-time PCR (q-PCR), while serum progesterone/estrogen levels were determined by respective commercial kits. Data were evaluated statistically. A total of 15.4 % RSA (GroupI) were diagnosed as C. trachomatis-positive (200 bp), whereas controls were uninfected. q-PCR showed significant upregulation (P<0.0001) of PGE2 (EP-1, EP-2, EP-3, EP-4), PGF2α (FP) and PGI2 (IP) receptors in Group I versus Group II. The expression of PG receptors increased significantly with advanced gestational age (P<0.002); however, only contractile receptors, EP-1, EP-3 and FP, were positively correlated with gestational age in Group-I. In infected RSA, mean serum progesterone level was significantly low (P<0.0001) while serum oestrogen was high (P<0.0001). Overall, the data suggest that increased expression of PG receptors, particularly contractile gene receptors (EP-1, EP-3, FP), with advanced gestational age and altered steroid levels could be a possible risk factor for abortion in Chlamydia-infected RSA.

Uptake and incorporation of arachidonic acid and of dihomogamma-linolenic acid into tissue lipids in uterine strips isolated from ovariectomized and from ovariectomized-diabetic rats. Effects of 17-beta-estradiol

The uptake of 14C-arachidonic acid (14C-AA) and 14C-dihomogamma-linolenic acid (14C-DGLA) into phospholipids (PLs) and neutral lipids (NLs) in uterine tissue obtained from ovariectomized controls (C) and from ovariectomized-diabetic rats (D) was studied. Uterine strips from D rats incorporate significantly less (P less than 0.05) 14C-AA into PLs than C rats. On the other hand the uptake of 14C-AA into NLs is significantly smaller (P less than 0.05) in uterine tissue from C than from D animals. The estrogenization of the C animals did not modify the incorporation of 14C-AA into PLs or NLs. On the contrary, uterine tissue obtained from D rats treated with 17-beta-estradiol incorporated significantly more labelled AA (P less than 0.05) into PLs and significantly less 14C-AA (P less than 0.05) into NLs than untreated D animals. The incorporation of 14C-DGLA into PLs shows similar pattern in uterine tissue obtained from C and D animals. Estrogenization increased significantly (P less than 0.01) in both cases, the incorporation into PLs. Regarding the incorporation of 14C-DGLA, it was clearly shown that DGLA is taken up significantly more (P less than 0.01) by NLs than by PLs, both in C and D rats. The estrogenization of C and D rats induces a significant decrease in the incorporation of 14C-DGLA into NLs in both experimental groups. The distribution of 14C-AA into the different subfractions of PLs is not uniform.(ABSTRACT TRUNCATED AT 250 WORDS)

In-vitro production of prostaglandin E, F and 6-oxo-prostaglandin F1 alpha by the uterine and ovarian tissues of pseudopregnant rabbits

The production of prostaglandin (PG) E, PGF and 6-oxo-PGF1 alpha by the uterine and ovarian tissues of pseudopregnant rabbits was investigated at the various stages of pseudopregnancy. The production of PGE, PGF and 6-oxo-PGF1 alpha in the tissues tested was expressed as mean (+/-S.E.M.) ng/mg protein per 6h. The production of PGE by endometrial tissue was found to be slightly raised with levels ranging from 2.15 to 2.92 on days 13 - 19 compared with values on day 5 (P less than 0.01). Subsequently PGE production declined on day 22 to the same level as that on day 5. In the myometrial tissue the same tendency in PGE production was observed as in the endometrial tissue. A significant increase in PGF production in the endometrial tissues was observed on day 13 (4.08 +/- 0.56) compared with that on day 12 (1.28 +/- 0.17) (P less than 0.001). The highest activity was detected on day 19 (7.19 +/- 0.29). An abrupt decrease occurred on day 20. In the myometrial tissues there was a slight and gradual increase in PGF production from day 12 (1.88 +/- 0.18) until day 16 (3.22 +/- 0.21). A sudden decline in the activity was detected after day 17. A marked increase of the 6-oxo-PGF1 alpha production activity in the myometrial tissues was observed on days 12 - 20 ranging from 14.60 to 19.25 compared with that on day 5 (P less than 0.001). The maximum activity was detected on day 16 (19.25 +/- 2.76). In the endometrium significant increase ranging from 4.85 to 8.31 occurred continuously from days 14 - 20 compared with that of day 12 (P less than 0.01). The myometrial tissue was shown to be significantly more potent in 6-oxo-PGF1 alpha production than endometrial tissue (P less than 0.01). No significant increase of PGE and PGF production activity was detected in the ovarian tissues throughout pseudopregnancy. The corpora lutea were shown to have very low 6-oxo-PGF1 alpha production activity. The 6-oxo-PGF1 alpha production activity of the remaining ovarian tissue was demonstrated to be significantly (P less than 0.01) more potent than the corpus luteum. The endometrial tissue of pseudopregnant rabbits has marked PGF2 alpha production activity in the late stage of pseudopregnancy, whereas the myometrial tissue is remarkably potent in 6-oxo-PGF1 alpha synthesis. Conversely, ovarian tissues showed much lower PG production activity than the uterine tissues. These experiments suggest that the main site of PGF production in luteolysis may be the endometrium and not the ovary itself. The physiological significance of PG production in relation to luteolysis is discussed.

The effect of estradiol on isolated rat uterine motility and on prostaglandin generation

The motility of isolated uterine horns as well as the generation of PGE and PGF like material by the uterus from estrus and spayed rats, treated or untreated with 17-beta estradiol, were studied. Following 40 minutes of mounting the spontaneous motility of uteri from estrus rats had a lower magnitude than that from spayed ones. The amount of PGF-like material was similar in both groups whereas the first one liberated less PGE-like substance. In spayed animals treated wth 1 microgram of 17-beta estradiol the decay of spontaneous c ontractile force was higher that that observed in untreated rats, and similar to that displayed by uteri from estrus. Less PGE-like material was liberated in comparison with spayed animals and a tendency to produce higher quantity of PGF-like compounds was observed, although the level was not significantly different. With 50 micrograms of 17-beta estradiol the spontaneous reduction of contractile activity was higher than in spayed animals and than in those treated with 1 microgram. The amount of PGF-like material liberated was higher than in spayed rats and less PGE-like substance was generated comparing with spayed and 1 microgram-treated animals. These findings show that estradiol decreases the release of PGE-like compound. It would also appear that this may have some relationship with the levels of spontaneous contractile activity of the isolated rat uterus.

The possible mode of action of phostaglandins. XII. Differential effects of phostaglandin F2alpha in inducing premature evacuation of conceptos in the intact and castrated pregnant rat

A single injection of 2.0 mg/kg prostaglandin F2alpha(PGF2alpha) on day 18 of pregnancy was consistent in inducing premature labor by 72 h following the injection. Conversely, castration before PGF2alpha on day 18 of pregnancy made the animals almost inert to PGF2alpha and only 20% of the treated animals showed premature evacuation of the conceptus. Injection of 10mug of estradiol cyclopentylpropionate (ECP) on day 18 was, however, found to be effective in emptying the gravid uteri of 100% castrated pregnants by 72 h. Indomethacin, a consistent inhibitor of prostaglandin biosynthesis and release, along with ECP in an identical experimental situation was found to be ineffective in reversing the ECP-induced premature parturition in castrated pregnants. The importance of intact ovary for the action of PGF2alpha concerning premature labor in rats has been discussed.

Effect of estrogen on activity of prostaglandin synthetase in rabbit oviduct

The activity of the prostaglandin synthetase system in the ampulla and isthmus of the rabbit oviduct has been studied in vitro. Thirty hours after an injection of estrogen the isthmus produced significantly more total prostaglandins following 9 minutes of incubation than the ampulla. These values were not, however, significantly different from those observed following 9 minutes of incubation in the same portions of the oviducts of estrous or castrate animals. Furthermore, the total yields of prostaglandins at thirty minutes did not differ significantly between treatment groups.

Changes in phospholipids and acyl group composition of rat mammary gland during pregnant, lactating, and post-weaning periods

The distribution of phospholipids as well as their fatty acid compositions of rat mammary tissues were examined during pregnant, lactating, and post-weaning periods. There was no apparent change in phospholipids and their acyl groups during the early and late pregnant periods. However, tissue phospholipid composition was different during pregnant, early, and late lactating periods. After parturition, there was a marked increase in the proportion of diacyl-glycerophosphorylcholine in the phospholipids of mammary tissue, but this proportion decreased gradually during lactation. The decrease in diacyl-glycerophosphorylcholine during lactation was marked by a corresponding increase in diacyl-glycerophosphorylethanolamie. Although the shorter chain fatty acids of triglycerides were increased during lactation, only a small proportion of these fatty acids was found in the phosphoglycerides. Marked changes in acyl group composition of individual phospholipids are found during these different physiological stages. In general, there was a rapid decrease in 20:4 and an increase in 18:2 in the major phosphoglycerides during parturition. The proportion of 20:4 in the phosphoglycerides remained low throughout the entire lactating period, while that of 18:2 continued to increase 2-3 fold. Most of the changes in acyl group of the phosphoglycerides during lactation returned to normal ca. 10 days after weaning. A possible relationship of the variation of phospholipid and acyl group compositions in mammary tissue to changes in hormonal pattern during different physiological stages is discussed.

Prostaglandin E2 in human gingiva in health and disease and its stimulation by female sex steroids

The levels of prostaglandin E2 were measured by means of radioimmunoassay in 12 clinically normal and 24 chronically inflamed human gingival tissue homogenates. The average values were found to be 16 and 285 pmol/gm wet weight of the normal and inflamed samples, respectively. Addition of estradiol-17beta alone or a mixture of estradiol-17beta and progesterone to incubation media containing normal or inflamed gingiva caused a significant increase in the in vitro synthesis of endogenous PGE2. Increased levels of female sex steroids during pregnancy may enhance gingival inflammation.

Effects of indomethacin and prostaglandin F2alpha on parturition in the hamster

In the hamster administration of indomethacin twice a day on days 14 to 16 of pregnancy delayed the onset of parturition; a delay of 5 and 8 hours was observed following treatments of 300 or 600 mug/injection of indomethacin, respectively. Injection of PGF2alpha to the indomethacin treated hamsters on day 15 of pregnancy, on the other hand, advanced the onset of parturition. Treatments of indomethacin and/or PGF2alpha did not affect the duration of parturition.

Periovulatory changes in ovarian prostaglandin formation and their hormonal control in the rat

The concentration of prostaglandins of the E-group (PGE) and F-group (PGF) and the activity of prostaglandin-synthetase in rat ovaries increased on the evening of the day of proestrus and reached a peak at 5.00 h on the following morning, i.e. about the time of ovulation. Enzyme activity and PG concentrations receded to basal levels by 10.00 h on the day of estrus. These changes were prevented when the proestrous gonadotropin surge was blocked by administration of nembutal, and could be restored by administration of either LH or of FSH freed of LH contamination. The spontaneous preovulatory rise in prostaglandin concentration was about 6-fold for PGF and 30-fold for PGE, compared with values observed during the remainder of the cycle, whichas the rise in prostaglandin synthetase activity was only about 1.7-fold. The LH effect on PG accumulation had a latency of 2-4 h, which argues for enzyme synthesis rather than activation of preformed enzyme as the mechanism responsible. The small magnitude of the change in enzymic activity suggests that LH may, in addition, augment the availability of PG precursors. The results are compatible with the concept that prostaglandins play a physiological role in the gonadotropin-induced process of follicular rupture.

Steroid-independent effect of gonadotropins on prostaglandin synthesis in rat Graafian follicles in vitro

The content of prostaglandins of the E-group (PGE) or F-group (PGF) was determined by radioimmunoassay in rat ovaries and in homogenates of cultured Graafian follicles. Intraperitoneal administration of luteinizing hormone (NIH-LH-S18; 10 mug/rat) at 9.00 h on any day of the estrous cycle caused an increase in ovarian PGE content within 5 h. The response was greatest on the day of proestrus (940% rise), i.e. when the ovary contains large follicles, and least at metestrus (80%). Follicles explanted from proestrous rats before the preovulatory gonadotropin surge responded to addition of LH (1-5 mug/ml) to the culture medium with a 10 to 30-fold increase in PGE and a 5-fold increase in PGF accumulation over a 5-h-period. Follicle stimulating hormone (NIH-FSH-S9; 10 mug/ml) caused a similar rise in follicular PGE accumulation, even after treatment of the FSH preparation with excess of an antiserum to the beta-subunit of LH. Stimulation of follicular PG accumulation was unimpaired during suppression of progesterone and estrogen synthesis by aminoglutethimide. It is concluded that these steroids play no part in the mediation of the LH-effect on follicular prostaglandin formation.

Prostaglandin F2alpha: modification of its abortifacient effect by depo-estradiol cypionate in rats

Insertion of a Silastic-PVP implant containing 150 mug PGF2alpha into one of the uterine horns or administration of a single subcutaneous injection of 4 mug of Depo-Estradiol Cypionate (ECP) did not induce abortion in pregnant rats. However, a combined treatment with 150 mug of PGF2alpha in a Silastic-PVP implant and 4 mug of ECP induced abortion in all treated rats. Apparently, ECP stimulated endogenous production of PGF and consequently enhanced the effect of the administered 150 mug of PGF2alpha. The release of 3H-PGF2alpha from Silastic-PVP implants was faster after intrauterine or intraperitoneal than after subcutaneous insertion. The release rate of 3H-PGF2alpha from Silastic-PVP implants in vitro was comparable to that observed after subcutaneous placement of similar implants. It is suggested that administration of estrogen combined with PGF2alpha might shorten the interval between treatment with PGF2alpha and abortion. Moreover, a Silastic-PVP implant would lend itself as a better method of administration, releasing PGF2alpha locally, slowly, and continuously.