Immunohistochemical localization of receptors for progesterone and oestradiol-17 beta in the implantation site of the rhesus monkey

The aim of the present study was to examine the cellular basis of the involvement of oestradiol and progesterone in blastocyst implantation in the primate. To this end, the cellular distribution of receptors for oestradiol (ER) and progesterone (PR) in fetal trophoblast cells and in endometrial compartments of timed lacunar (pre-villous) and villous stages of placentation in primary implantation sites collected on days 13-22 of gestation were investigated in rhesus monkeys. Both in pre-villous stage tissue and in villous stage tissue, cytotrophoblast cells and syncytiotrophoblast cells and other trophoblast derived cells were PR positive, while they were generally ER negative. Maternal endometrial cells were ER negative, while epithelial cells, stromal cells and vascular endothelial cells in maternal endometrium showed heterogeneous staining patterns for PR depending on their relative location; these patterns, however, correlated well with glandular hyperplasia and differentiation, stromal-decidual transformation and vascular response seen during blastocyst implantation.     

Reversible suppression of menstruation with progesterone antagonists in rhesus macaques

BACKGROUND: A reliable means of menstrual suppression would greatly improve the quality of life for women. Information is lacking on the direct endometrial effects and appropriate dosages of new antiprogestins that may be useful for this purpose. METHODS: The current work evaluated three different systems in macaque monkeys. First, the range of doses of two relatively new antiprogestins, ZK 137 316 and ZK 230 211, that would block progesterone action directly on the endometrium in artificially cycled, spayed rhesus macaques; second, the direct endometrial effects of ZK 230 211, a type III antiprogestin; and third, investigation of whether endometrial-suppressive doses administered chronically to intact, cycling monkeys could be used for reversible, menstrual suppression. RESULTS: The results in naturally cycling animals showed that ZK 137 316 blocked menstruation in all animals, but doses of 0.05 mg/kg blocked ovulation in 55.5% of animals and doses of 0.1 mg/kg blocked ovulation in 66.6% of the animals. However, all doses of ZK 230 211 that blocked menstruation also blocked ovulation. All progesterone antagonist (PA)-treated animals, regardless of dose, maintained normal follicular phase concentrations of oestradiol and returned to normal menstrual cyclicity within 15--41 days post-treatment.Therefore ZK 137 316, depending on dose, can allow ovulation but block menstruation, while ZK 230 211, a much more potent PA, blocks both ovulation and menstruation at all effective doses. Both PAs block unopposed oestrogenic action on the endometrium through their antiproliferative effects. CONCLUSIONS: Reversible amenorrhoea can be achieved with these two PAs, and they can protect the endometrium from the effects of unopposed oestrogen whether or not ovulation is blocked. Chronic, low dose PA treatment may provide a new option for women who wish to suppress their menstrual periods.     

Effect of tamoxifen alone and in combination with RU 486 on the endometrium in the mid-luteal phase

The effects of RU 486 combined with tamoxifen and tamoxifenalone on hormonal parameters and endometrial development atthe time of implantation were studied. Measurements of cytosolicoestrogen and progesterone receptors in endometrium and placentalprotein 14 (PP14) in plasma were also included. Three dosageschedules were used: single oral dose of 40 mg tamoxifen aloneand in combination with 200 mg RU 486, and 40 mg tamoxifen forthree consecutive days starting on the first day after the luteinizinghormone (LH) surge. The combined treatment prolonged the lutealphase (P < 0.05) and increased the plasma levels of progesterone.A single dose of tamoxifen did not affect the bleeding patternand plasma hormone levels, but raised plasma oestradiol andLH with the 3-day treatment. The endometrium was retarded afterthe combined and the 3-day treatment with tamoxifen. Concentrationsof cytosolic progesterone receptors were higher after the combinedtherapy, but were unaffected after tamoxifen only. PP14 levelswere higher (P < 0.05) after repeated tamoxifen doses thanin controls, but were lower with combined treatment. Progesteroneand oestrogen are evidently necessary for endometrial maturationduring the secretory phase of the menstrual cycle. PP14 levelsin plasma cannot be used for clinical assessments of endometrialfunction because high levels coincide with disturbed endometrialdevelopment.     

Autoradiographic localization of [3H]RU 486 and [3H]progesterone in the uterus, pituitary and hypothalamus of the rat

Twenty-one castrated oestrogen-primed Wistar rats, which were2-months-old, were injected via the jugular vein with 100 µCi/100g body weight of [³H]RU 486 or [³H] progesterone. Some of thesereceived unlabelled compounds for competition studies. Samplesof reproductive tract, pituitary and hypothalamus were excisedafter 15 min. The 4-µm frozen sections were processedfor thaw-mounted autoradiography. The exposure time of the autoradiogramwas {small tilde}6 months. After the injection of [³H]RU 486and [³H]progesterone, the nuclear concentration of radioactivitywas most distinct in muscular and stromal cells of the uterus,and the epithelial nuclei of lumina and glands showed weak labelling.Nuclear localization was also observed in muscle cells of thevagina, cervix and oviduct. After injection of [³H]progesterone,the radioactivity was found in the nuclei and cytoplasm of anteriorpituitary cells and some cells showed a preferential nuclearconcentration of radioactivity. The distribution of [³H]RU 486in the anterior pituitary was more extensive than that of [³H]progesterone.In the hypothalamus, specific localization of [³H]RU 486 and[³H]progesterone existed in neurones accumulated in the preopticnucleus, preoptic suprachiasmatic nucleus and the periventricularnucleus. No localization was found in the diaphragm. Pretreatmentwith RU 486, but not with dexamethasone, reduced the nuclearconcentration of radioactivity of [³H]progesterone in the vagina,uterus, oviduct, pituitary and hypothalamus. The nuclear concentrationof radioactivity after injection of [³H]RU 486 was also decreasedby preinjection with progesterone. The autoradiographic resultssuggest that RU 486 and progesterone competed for the specificbinding site (possibly a progesterone receptor) in the targetcells at the levels of the uterus, pituitary and hypothalamusin vivo.     

Pregnancy: The effect of RU486 on progesterone and oestrogen receptor concentration in human decidua on early pregnancy

Concentrations of progesterone receptor (PR) and oestrogen receptor(ER) were measured by radioligand assay in decidual tissue ofwomen undergoing termination of early pregnancy (amenorrhoeaup to 49 days). Pregnancies were terminated by vacuum aspirationat 12 or 36 h after oral administration of placebo or antiprogestinRU486 in different doses. Treatment with RU486 decreased decidualPR content, the effect being observed at 12 h as well as at36 h after 600 mg RU486 and at 36 h after 3 x 25 mg RU486 givenat 12 h intervals. PR concentration 12 h after a single doseof 25 mg RU486 was not affected. ER content was unchanged at12 h after RU486 but increased 36 h after 600 mg and 3 x 25mg RU486. Our data suggest that apart from blocking progesteroneaction, RU486 may exert its abortifacient effect through decreasingthe PR concentration. The simultaneous decrease of PR concentrationand an increase of ER concentration changes the balance betweenthem in favour of ER, which might also play a role in the abortifacienteffect of RU486.     

Disparate actions of mifepristone (RU 486) on glands and stroma in the primate endometrium.

Besides being an antiprogestin, mifepristone (RU 486) was recently shown to antagonize oestrogen-dependent growth in the endometrium. To explore the molecular mechanisms for this phenomenon, we investigated whether or not the morphological effects of mifepristone are mediated by the progesterone receptor (PR) and whether mifepristone has disparate effects on the glandular epithelium and stroma. Six groups of hypogonadal, oestrogen-primed cynomolgus monkeys were treated for 2 weeks with: vehicle only (group I); mifepristone (group II); mifepristone plus progesterone at 0.2 mg/kg (group III), 1.0 mg/kg (group IV) or 5.0 mg/kg (group V); and progesterone only (5.0 mg/kg) (group VI). Histomorphological evaluation showed strikingly compacted stroma in the mifepristone-exposed endometria (group II), which was partially reversible by additional progesterone treatment (groups III-V). Glandular proliferation (pseudostratification, glandular mitoses) in mifepristone-treated monkeys was not significantly different from that in vehicle (oestradiol)-treated monkeys, but was inhibited by progesterone-only treatment. Cells containing vacuoles were scarce in the mifepristone-exposed endometrium, but detected frequently in progesterone-exposed endometria, indicating the strong antisecretory effect of mifepristone on glands. We conclude that oestrogen-dependent oedema in the stroma is antagonized by mifepristone. The reversal of this effect by progesterone suggests a PR-mediated mechanism. In glands, mifepristone is antiprogestogenic, but not antioestrogenic. Thus, stromal cells may be the target of antiprogestin-induced inhibition of oedema and endometrial growth.     

Anti-nidatory effect of a single, early post-ovulatory administration of mifepristone (RU 486) in the rhesus monkey

The hypothesis that post-coital administration of mifepristone(RU 486) as a single dose in the early luteal phase can be aneffective anti-nidatory strategy was tested using the rhesusmonkey as the experimental model. Incidence of pregnancy, vaginalbleeding patterns, profiles of menstrual cyclicity and of serumlevels of progesterone and oestrogen were examined followingadministration of RU 486 as a single dose of 10 mg/kg and 2mg/kg body weight on the second day after ovulation. In controlmonkeys (group 1; n = 5) receiving the vehicle alone (benzylbenzoate: olive oil, 1: 4, v/v) there was a 60% pregnancy rate.Following s.c. administration of RU 486 at both doses, no pregnancywas recorded in a total of 33 treatment cycles in 12 monkeys.Five monkeys received RU 486 at 10 mg/kg s.c. (group 2) in threeconsecutive cycles. All animals had complete inhibition of implantation;in addition, the treatment cycle length was prolonged (P <0.001) due to an extension of the luteal phase. The subsequentfollicular phase was unaffected. Mild, premature vaginal bleedingduring the luteal phase was recorded in five treatment cycles,3–5 days after drug application. Though the serum profilesof progesterone and oestrogen in these monkeys showed markedindividual variations, there was a characteristic progesteronerebound about 18–20 days after drug administration. Monkeysin group 3 were given RU 486 at 2 mg/kg, s.c. either for threeconsecutive cycles (group 3a; n = 4) or for two consecutivecycles (group 3b; n = 3). Premature luteal phase vaginal bleedingoccurred only in four treatment cycles, within 2–6 dayspost-treatment. An increase in both the duration (P < 0.001)and degree (P < 0.001) of menstrual flow as compared withthe pre-treatment cycles was recorded in six treatment cyclesof three monkeys in group 3. These animals did not have prematureluteal phase vaginal bleeding. Collectively, 100% protectionagainst pregnancy with no change in the cycle length was obtainedin all seven monkeys in 18 treatment cycles. Analysis of pooleddata revealed that the subsequent follicular phase, as wellas the ovarian steroid hormone profiles of treatment cycleswere unaffected. Thus, a single application of RU 486 in theearly secretory phase appears to be a potential anti-implantationstrategy for intercepting pregnancy in the primate.     

The effect of RU 486 on progesterone receptor in villous and extravillous trophoblast

A total of 60 women with 6–7 weeks' amenorrhoea were randomlyallocated to three groups. The women in the first group (control)took a placebo 24 h before undergoing vacuum aspiration. Thesubjects in the second and third groups were given orally 200mg of RU 486, 12 or 24 h before surgical interruption of theirpregnancy. Villi and decidua were collected and frozen in liquidnitrogen. There were no significant differences in villous cytosolicsteroid concentrations between the control and RU 486-treatedgroups. The RU 486 concentration was lower in villous cytosolthan in decidua and serum. The immunostaining of progesteronereceptor in villous and extravillous trophoblast was weak andlocalized in both cytoplasm and nucleus. RU 486 treatment hadno effect on the immunostaining of progesterone receptors introphoblast populations except in the placental bed giant cells,where the weak and diffuse progesterone receptor staining inthe cytoplasm of controls seemed to be concentrated in the nucleusafter RU 486 treatment. In conclusion, RU 486 might have noeffect on the immunostaining of progesterone receptor and onsteroid concentrations in villi in vivo.     

Effect of RU 486 on the endometrial response to deciduogenic stimulus in ovariectomized rhesus monkeys treated with oestrogen and progesterone.

Using the artificial plaque--decidual cell model in rhesus monkeys, the potential role of progesterone in the process of of epithelial and stromal cell responses was investigated by time-adjusted application of an antiprogestin, RU 486. Epithelial plaque formation is an immediate response of the endometrium to either trauma or invading trophoblast cells. To study this process, RU 486 (2.5 mg/kg body weight) or vehicle (ethanol/saline, 7:3, v/v, i.m.) was administered to the first group of monkeys immediately following traumatization (days 16 and 17 of treatment cycle). Histometric analysis revealed that treatment with RU 486 led to significant inhibition (P less than 0.001) in the recruitment of epithelial cells into plaque acini and consequent reduction (P less than 0.001) in the spread of the plaque reaction compared with control monkeys. In the second group of monkeys, experimental treatment was delayed until plaque formation had occurred (days 21 and 22 of cycle). RU 486 induced increased degeneration (P less than 0.01) in plaque cells. Thus the transformation and the maintenance of the epithelial plaque response appears to be progesterone-dependent. Glandular epithelium showed only marginal changes (P less than 0.05) in maximum cell height, amount of pseudostratification and secretory activity of glands as a consequence of RU 486 treatment; however, the antiprogestin induced a higher incidence of glandular apoptosis (P less than 0.01 for both groups). It has been suggested that the higher degree of apoptosis in the glandular epithelium could be a consequence of the progesterone receptor blocking action of RU 486. No distinctive change in endothelial cell ultrastructure was evident following RU 486 treatment; however, venular diameter was significantly increased (P less than 0.01, group I; P less than 0.001, group II) along with an apparent reduction in the extent of oedema. There was increased extravasation (P less than 0.01) and leukocytic infiltration (P less than 0.001, group I; P less than 0.05, group II) following RU 486 treatment. RU 486 induced vascular responses and increased diapedesis could presumably have resulted from its progesterone blocking action in vascular cells. RU 486 accelerated the incidence (P less than 0.01) of stromal decidualization (group I), as well as quantitatively accentuating (P less than 0.001) the decidual cell reaction (group II). It is possible that RU 486 may inhibit specific functions of decidual cells, despite morphologically consistent decidual transformation.     

The role of pre-ovulatory progesterone in the midcycle gonadotrophin surge, ovulation and subsequent luteal phase: studies with RU486 in rhesus monkeys

Conflicting evidence exists on the possible physiological roleof progesterone in the regulation of the midcycle surge of gonadotrophinsduring the normal primate menstrual cycle. We designed the presentstudy based on the availability of a potent antiprogesterone,RU486, that acts by binding to the progesterone receptor withoutinducing progestational activity. Regularly cycling rhesus monkeysreceived daily administration of RU486,10 mg orally (n = 8)or vehicle (n = 5) from the day of the menstrual cycle in whichserum oestradiol was 130 pg/ml or more, and a laparoscopy revealedthe presence of a dominant follicle. While vehicle administrationdid not affect the normal ovulatory pattern nor the hormonalmilieu of the menstrual cycles, RU486 induced marked aberrationsduring the treated cycles. Delay of ovulation with a normalsubsequent luteal phase was observed in three animals. Threeanimals remained anovulatory until the following cycle and twoanimals that ovulated on days 14 and 16 of the treated cycleshad short luteal phases. Analysis of daily FSH, LH, oestradioland progesterone revealed that the administration of RU486 disruptedthe midcycle pattern of gonadotrophins by disrupting them afterthe surge was initiated. Oestradiol surges were not differentfrom controls and in all animals the ascendant levels of progesteronewere interrupted by the administration of the antiprogesterone.This study clearly shows that the pre-ovulatory administrationof RU486, a potent antiprogesterone, alters pre-ovulatory gonadotrophinsecretion, inducing different degrees of menstrual irregularitiessuch as anovulation, delayed ovulations and short luteal phases.Based on these results it is possible to speculate that progesteroneexerts a facilitatory effect (positive feed-back) on the midcyclegonadotrophin peak that induces ovulation in primates.     

Effects of the progesterone antagonists onapristone (ZK 98 299) and ZK 136 799 on surgically induced endometriosis in intact rats

The effects of the progesterone antagonists (antiprogestins)onapristone (ZK 98 299) and ZK 136 799 on surgically inducedendometriosis were studied in intact female rats. Endometriosiswas induced by transplanting homologous endometrium to the parietalperitoneum of the abdominal wall (location A) and to the mesenteryof the small intestine (location B). The animals were treateddaily for 4 weeks at doses of 0.4 and 2.0 mg onapristone orZK 136 799. The growth of the endometriosis-like foci was measuredwith a calliper during both pre- and post-treatment laparotomy.Both antiprogestins exerted inhibitory effects on the growthof the endometriosis-like foci in terms of complete remission.A 40 and 50% remission of endometriosis was observed at eachlocation after the administration of 2.0 mg onapristone, whereas50 and 63% (location A) and 50 and 75% (location B) remissionswere found after the administration of 0.4 and 2.0 mg of ZK136 799 respectively. ZK 136 799 was also more potent than onapristonein growth inhibition (85 versus 48% for location B) in animalswith persistent endometriosis. Growth inhibition of the endometriosis-likefoci was confirmed by histology and immunohistochemical stainingof the proliferating cell nuclear antigen. The antiprogestinscaused a reduction in glandular and luminal epithelial cellsin the ectopic endo-metrium. Both antiprogestins tended to causea decrease in uterine weight. Unlike the inhibitory effectsin the ectopic endometrium, both onapristone and ZK 136 799exhibited some stimulatory effects on the epithelial cells withinthe eutopic endometrium. Serum 17-oestradiol concentrationsdid not vary significantly among the different treatment groups.No antiglucocorticoid effect of the antiprogestins was observedat either dose. This study indicates that the antiprogestinsonapristone and ZK 136 799 exhibit antiproliferative effectsin the ectopic but not the eutopic endometrium via mechanismswhich remain to be established. The better efficacy of ZK 136799 is more likely caused by its higher antiprogestagenic activitythan its partial androgenic activity. These findings may bea further indication of the future potential of antiprogestinssuch as onapristone and ZK 136 799 in the treatment of endomet-riosis.     

Contraception: Endometrial microvascular density during the normal menstrual cycle and following exposure to long-term levonorgestrel

The mechanisms that underlie progestogen-induced endometrialbreakthrough bleeding are poorly understood. The aim of thepresent study was to quantify endometrial microvascular densityin 54 controls and 42 women with 3–12 months' exposureto Norplant (levonorgestrel subdermal contraceptive implant)and to correlate it with bleeding pattern, endometrial histology,and peripheral plasma oestradiol and progesterone concentrations.Endometrial biopsies were processed routinely and sections immunostainedusing anti-CD34 antibody to identify vascular endothelial cells.Menstrual record card data were analysed using World HealthOrganization definitions. The mean microvascular density (±SEM) for control samples was 186 ± 8 vessels/mm², andthere were no significant differences across the cycle. Norplantuser's endometrial microvascular density was significantly elevatedabove controls (294 ± 18 vessels/mm², P = 3.36 x 10^–8).Endometrial microvascular density in Norplant users did notcorrelate with oestrogen concentrations prior to biopsy, bleedingpatterns or endometrial histology. The results from this studyshow that women receiving Norplant have significantly increasedendometrial microvascular density compared to controls. Anotherfinding from this study was that bleeding in Norplant usersoften occurred from thin atrophic endometrium. These resultsprovide new insights into the physiological mechanisms thatmay be involved in progestogen-induced endometrial bleeding.     

Implantation: Effects of a single post-ovulatory dose of RU486 on endometrial maturation in the implantation phase

The effect of a single post-ovulatory dose of RU486 on endometrialmaturation was studied in the implantation phase. A total of11 healthy women were followed for one control and one or twotreatment cycles. In treatment cycles, a dose of 200 or 400mg RU486 was administered on day luteinizing hormone (LH) +2.In both control and treatment cycles, an endometrial biopsywas obtained on LH+ 6to LH+8. These biopsies were assessed bymorphometric and immunohistochemical analyses. The treatmentwith RU486 did not disturb the normal menstrual rhythm but causeda significant inhibition in the endometrial development. Glandularprogesterone receptor staining was significantly more pronouncedafter RU486 treatment, while there was a reduction in the Dolichosbiflorus agglutinin lectin binding, indicating inhibition ofthe normal secretory transformation of the endometrium. It islikely that these effects on endometrial development and secretoryactivity represent the basis of the contraceptive effect ofpost-ovulatory RU486 treatment.     

Is the measurement of oestradiol/progesterone ratios in the peri-implantation period of any value in predicting endometrial development?

To examine the value of the measurement of oestradiol/progesteroneratios in the peri-implantation period, three different typesof cycle were studied; natural cycles (n = 13), cycles treatedwith anti-oestrogens (n = 19), and artificial cycles (n = 41)produced by six different hormone replacement regimens. Normalendometrial development was found to occur across a wide rangeof oestradiol/progesterone ratios. There was no significantcorrelation between the oestradiol/progesterone ratios and resultsof endometrial dating. The results suggest that oestradiol/progesteroneratios are of limited value in predicting endometrial developmentat the time of implantation.     

Implantation and early pregnancy: Effect of single-dose, early luteal phase administration of mifepristone (RU486) on implantation stage endometrium in the rhesus monkey

The characteristics of implantation stage endometrium followinga single-dose, early luteal phase application of mifeprlstone(RU486) in proven conception cycles has been examined in therhesus monkey in an attempt to understand the physiologicalbasis of the anti-implantation activity of the drug. Endometrialsamples were collected from monkeys subjected to vehicle (group1, n±14) and RU486 (2 mg/kg body weight; group 2, n±12)on day 2 after the presumed day of ovulation of successfullymated cycles. The average diameter of glands (P <0.05), numberof vacuolated cells (P <0.01), number of supranuclear vacuolatedcells (P <0.05) in glandular epithelium and amount of glandularsecretion (P <0.05) were significantly lower in RU486-treatedendometrium compared with control tissue samples. Additionally,18% of glandular epithelial cells showed apoptotic and degenerativefeatures in RU486-treated tissue samples. These data, togetherwith the observed significant decreases in precipitate area(P <0.02) and in the optical absorbance of alkaline phosphatasereaction end-product (P <0.05), confirm that retardationin glandular differentiation in the upper functionalls is alikely target of antiprogestin action in implantation stageendometrium. An increased frequency of mitosis in stromal cells(P <0.05) and a greater degree of extravasation (P <0.05)were also observed after RU486 exposure. Despite an apparentindication of constriction and regression in few RU486-exposedendometria compared with controls, morphometric analyses didnot show any changes in capillary structure. Whether endometrialvasculature in progesterone-exposed uterus is a target of antiprogeslinaction during the pen-implantation stage remains to be determined.Further studies are required to explain the observed increase(P <0.02) in the area of precipitate of von Willebrand (vW)factor with no change in vW factor-positive vessels, and theapparent increase in collagen IV immunostain in subepitheliaiand perivascular basement membrane in Implantation stage endometriumafter early luteal phase RU486 treatment in monkeys.     

The effect of RU486 on the gene expression profile in an endometrial explant model

Administration of RU486 in vivo during the receptive phase rapidly renders the endometrium non-receptive to the implanting embryo. In order to identify key pathways responsible for endometrial receptivity we have used cDNA arrays to monitor gene expression changes in short-term endometrial explants in response to RU486. Endometrial biopsies from five normal fertile women at mid-secretory phase were cultured in the presence of estradiol and progesterone with or without RU486 for 12 h. cDNA arrays were produced containing approximately 1000 sequence-verified clones which included genes known to be important in angiogenesis, apoptosis, cell signalling, extracellular matrix remodelling and cell cycle regulation. cDNA probes from the paired endometrial samples were hybridized to the arrays and hybridization signals were quantified. A total of 12 genes displayed significant changes in expression; six were up-regulated and six down-regulated following RU486 treatment. For five of these genes this is the first report suggesting that they are regulated by steroids in the endometrium. JAK1 and JNK1 were two of the genes shown by the arrays to be down-regulated in RU486-treated endometrial explants. This was confirmed by real time RT-PCR. JAK1 immunoreactivity was localized to both glandular epithelium and the stroma of normal endometrium and staining was much stronger in the luteal phase of the cycle. These results show that components of two important signalling pathways in endometrium-the JAK/STAT pathway, and the JNK pathway-are altered by RU486. Genes whose expression is controlled by these pathways are likely to be involved in the mechanism by which steroids render the endometrium receptive to the implanting embryo.     

Efficacy of progesterone antagonist RU486 (Mifepristone) for pre-operative cervical dilatation during first trimester abortion

A randomized doubbblind study (RU486 versus plaebo) was carriedout in order to investigate whether a progesterone antagonistfacilitated surgical abortion in the first trimester of pregnancy.The consistency of the cervix changed significantly after RU486(P < 0.02). We conclude that this effect may facilitate cervicaldilatation, making first trimester abortion under local anaesthesiamore comfortable and less dangerous.     

Endometrial oestrogen and progesterone receptors and their relationship to sonographic appearance of the endometrium

The rapid development of ultrasonographic equipment now permits instantaneous assessment of follicles and endometrium. The sonographic appearance of the endometrium has been discussed in relation to in-vitro fertilization (IVF) cycles. However, a generally agreed view of the relationship of the sonographic appearance to fecundity in IVF cycles has not emerged. We have studied the relationship between steroid receptors and the sonographic appearance of the preovulatory endometrium in natural cycles and ovulation induction cycles. Preovulatory endometrial thickness was not found to be indicative of fecundity, although a preovulatory endometrial thickness of <9 mm related to an elevated miscarriage rate. The preovulatory endometrial echo pattern did not predict fecundity. No relationships were found among endometrial appearance, endometrial steroid receptors and steroid hormone concentrations in serum. Oestrogen or progesterone receptor concentrations were not related to endometrial thickness or to concentrations of serum oestradiol, the only significant correlation being found between the endometrial concentrations of oestrogen and progesterone receptors. The ratio of progesterone:oestrogen receptor concentration was somewhat less in echo pattern B (not triple line) endometrium compared with pattern A (triple line) endometrium. Oestrogen and progesterone receptor concentrations appeared stable on gonadotrophin induction, though fewer numbers were found during clomiphene cycles than in natural cycles. With regard to the distribution of receptor concentration between clomiphene and natural cycles, most women using clomiphene had very low oestrogen receptor populations. Pregnancy rates were low, in spite of high ovulatory rates during clomiphene treatment and were mainly related to low oestrogen receptor concentrations in preovulatory endometrium.     

The effect of RU486 administered during the proliferative and secretory phase of the cycle on the bleeding pattern, hormonal parameters and the endometrium

Seventeen healthy women aged 24–45 years with regularmenstrual periods, proven fertility and not using steroidalcontraceptives or IUD were recruited for the study. The volunteerswere followed during one control, one treatment and one follow-upcycle. Daily morning urine samples were obtained during thecontrol and the treatment cycle. The samples were analysed withregard to pregnanediol glucuronide (P₂-G), oestrone glucuronide(E₁-G), oestradiol (E₂), progesterone (P₄), LH and creatinine.During the entire 3-month study the subjects kept a record ofuterine bleeding and side effects. The subjects received 50mg RU486 daily either on cycle days 7–10 (n = 7) or oncycle days 20–23 (n = 10). An endometrial biopsy was takenon cycle day 10 in the first group and on cycle days 21–28in the second group of patients. Treatment during the proliferativephase caused significant prolongation of the cycle length dueto a delay of the oestrogen and LH surge. However, once theoestrogen concentration started to increase, the remaining partof the cycle was normal. The length of the follow-up cycle wassimilar to that of the control cycle. The morphology of theendometrium did not differ from control samples taken from untreatedwomen at the same time of the cycle. All ovulating women (n= 9) treated in the mid-luteal phase started to bleed on the3rd to 4th day of the treatment. In four of these women thebleeding was scanty and followed by a menstrual-like bleedingat expected time, while in the remaining five volunteers thetreatment bleeding was heavier and not followed by a new bleedinguntil a month later. The duration of the secretory phase was16.5 ± 1.3 days in women with two bleeding episodes and11.8 ± 1.9 days in women with one bleeding episode (P< 0.05). The hormonal parameters were similar in both groupsup to the start of the treatment. In the patients with one bleedingepisode, the treatment was associated with a reduction in progesteroneconcentration, while in the patients with two bleeding episodesthe progesterone concentration remained elevated until the secondbleeding episode. Light microscopic examination of the endometriumrevealed unique changes in the endometrial morphology. The resultsindicate that RU486 acts mainly on the endometrium but a director indirect effect on the corpus luteum cannot be excluded.The age of the corpus luteum may be of importance for its susceptibilityto RU486 treatment.