The effect of progestins on vascular endothelial growth factor, oestrogen receptor and progesterone receptor immunoreactivity and endothelial cell density in human endometrium

One common side-effect of contraceptive use is that it often leads to disrupted endometrial bleeding patterns. This may be due to changes in endothelial density and vessel integrity. To investigate whether the level of endometrial immunoreactive vascular endothelial growth factor (VEGF), oestrogen receptor or progesterone receptor (PR) have any role in this, women were treated with either Mircette, a monophasic oral contraceptive, or Implanon, a long-acting gestagen, and immunohistochemistry performed. In addition a small number of endometria were studied from women treated with levonorgestrel released from an intrauterine coil. During the untreated normal cycle, there was a significant increase in glandular VEGF immunoreactivity and a significant decrease in PR immunoreactivity in the midand late secretory phases compared to the proliferative phase. There was a significant positive correlation between stromal VEGF immunoreactivity and endothelial cell density. This correlation was also apparent during treatment with Implanon, but not with Mircette. Disrupted bleeding patterns were associated with Implanon and to a lesser extent with Mircette. Both contraceptives significantly reduced glandular VEGF immunoreactivity but the intrauterine treatment with levonorgestrel resulted in strong glandular epithelial staining and intense staining of decidualized stromal cells. Implanon significantly increased glandular PR staining, but Mircette significantly reduced stromal PR staining when compared to secretory phase before-treatment biopsies. There were no changes in endothelial cell density or glandular or stromal ER during the normal cycle, or with use of either contraceptive. There was no association of the parameters measured with bleeding patterns or histological category.     

Lack of correlation between vascular endothelial growth factor production and endothelial cell proliferation in the human endometrium.

The role of vascular endothelial growth factor (VEGF) in endometrial angiogenesis was examined by measuring its production in human endometrial tissues from different stages of the menstrual cycle and relating these data to endothelial cell proliferation in the same tissues. Conditioned medium was collected from explant, and separated glandular epithelial and stromal cells cultured from 24 normal human endometrial biopsies and VEGF measured by enzyme-linked immunosorbent assay (ELISA). Immunohistochemistry was also used to assess VEGF and the percentage of proliferating microvessels in the samples. Wide variation in results between individual endometrial samples at each stage of the menstrual cycle was observed for all parameters measured. There was no significant difference in VEGF secretion by explant, glandular epithelial or stromal cell cultures across the menstrual cycle, or in the percentage of proliferating vessels. VEGF immunostaining in the stroma was elevated during the early proliferative stage (P = 0.03). Epithelial cells secreted more VEGF than stromal cells (1.76 +/- 0.46 versus 0.46 +/- 0.06 ng per 10(5) cells; P = 0.002). There was no correlation between VEGF secreted by cultured explants, epithelial or stromal cells, VEGF immunostaining and the proportion of proliferating microvessels. These results show that the majority of endometrial VEGF is produced by glands, but neither total glandular nor stromal VEGF is correlated with endometrial endothelial cell proliferation. There is still no clear understanding on the regulation of human endometrial angiogenesis.     

Membrane-type matrix metalloproteinases and vascularization in human endometrium during the menstrual cycle

Endometrial angiogenesis is essential for a vascularized receptive endometrium. Previously, we described that membrane type-3 metalloproteinase (MT3-MMP) is associated with endometrial angiogenesis in vitro. The association of MT-MMPs with endometrial angiogenesis in vivo is unknown. Therefore, this study analysed the presence of MT-MMPs in human endometrium and their correlation with neovascularization. RNA/protein expressions of the six MT-MMPs were determined in cultured endometrial cells. Vascularization parameters and MT-MMP expressions in vivo were evaluated by immunohistochemistry in serial endometrium sections. MT1-, MT2-, MT3- and MT4-MMP antigens were expressed in cultured endometrial endothelial cells. MT2-, MT3- and MT4-MMP were expressed by endothelium during the proliferative and secretory phase. Strikingly, these phases showed elevated vascularization, elevated total vascular surface in proliferative phases, elevated number of vessels in proliferative/late secretory phases and increased luminal surface in the proliferative phases. All MT-MMP antigens were expressed in various endometrial cell types in vivo, with decreased levels during the early secretory phase. In conclusion, all MT-MMPs are expressed in endometrium in a cycle-dependent pattern. The vascular expression of MT2-, MT3- and MT4-MMP correlated with angiogenic episodes of the cycle. Since MT2- and MT3-MMP are known to regulate tube formation, these findings support earlier in vitro data on the role of MT3-MMP in endometrial angiogenesis. Additionally, MT2-MMP appears to be associated with endometrial neovascularization also.     

The effect of hormone replacement therapy on the immunoreactive concentrations in the endometrium of oestrogen and progesterone receptor, heat shock protein 27, and human beta-lactoglobulin

We determined the expression of oestrogen receptor (ER), progesterone receptor (PR), heat shock protein 27 (HSP27) and human beta-lactoglobulin in the endometrium under hormone replacement therapy (HRT). The immunohistochemical expression during the late progestogenic phase of sequential HRT was compared semi-quantitatively and using image analysis, to the early, mid-, and late luteal phase of the physiological cycle. Under sequential HRT, smaller glands were positive for the ER but larger glands with more advanced secretory features were negative. ER expression was lower in the stroma under HRT, and the difference was statistically significant compared with the early luteal phase (P < 0.05). Expression of HSP27 under HRT was lower in the epithelium but higher in the stroma compared with the physiological luteal phase. Epithelial PR expression was lower under HRT compared with the early, but not the mid- or the late luteal phase. The number of PR-positive stromal cells under HRT was lower compared with the physiological cycle, and the difference was statistically significant in comparison with the early luteal phase (P < 0.05). The glandular area expressing human beta-lactoglobulin during the late progestogenic phase was statistically significantly higher compared with the early, but lower in comparison with the mid- or the late luteal phase (P < 0.05). The study demonstrates a sub-physiological progestogenic response superimposed on evidence of a hypo-oestrogenism, and a differential response in the epithelium and stroma.     

Differential expression of angiopoietins 1 and 2 and their receptor Tie-2 in human endometrium

Angiogenesis, the growth of new capillaries from pre-existing blood vessels, is a physiological process involved in both normal menstrual cycling and implantation of the embryo. So far, very little is known about the expression of angiopoietins, growth factors involved in angiogenesis, in human endometrium. Both angiopoietin-1 (Ang-1) and angiopoietin-2 (Ang-2) are ligands for the endothelial cell-specific receptor tyrosine kinase Tie-2. In this study we determined the mRNA expression of Ang-1, Ang-2 and Tie-2 by quantitative competitive RT/(QC)-PCR (including specifically designed competitor cDNA) in biopsied human endometrium throughout the menstrual cycle. We detected the mRNA for the angiopoietins in 30 out of 32 endometrial biopsies (94%), covering early proliferative (n = 4), mid proliferative (n = 12), late proliferative (n = 3), early secretory (n = 3), mid secretory (n = 5) and late secretory (n = 3) phases. Analysis of the target/competitor ratios (QC-PCR) revealed that Ang-1 mRNA expression was significantly up-regulated (P = 0.027) during the secretory phase of the menstrual cycle. In contrast, the expression levels of both Ang-2 mRNA and Tie-2 mRNA showed only minor variations at different cycle stages. These findings were confirmed by the relative expression ratio of Ang-1 versus Ang-2 in a multiplex PCR. The expression of Ang-1, Ang-2 and Tie-2 mRNA was detected in both isolated endometrial epithelial and stromal cell fractions. Immunohistochemical localization of the proteins revealed qualitative differences in both cell type and cycle stage expression. In conclusion, the enhanced Ang-1 expression during the secretory phase might serve to stabilize the newly developed blood vessels.     

Angiogenesis, vascular endothelial growth factor and the endometrium

Angiogenesis is an essential component of endometrial renewal. The formation of new vessels depends on interactions between various hormones and growth factors, and this review focuses on the expression of angiogenic growth factors in the human endometrium. Peptide and non-peptide angiogenic factors interact during endometrial renewal, including epidermal growth factor (EGF), transforming growth factors (e.g. TGF-beta), platelet-derived endothelial growth factor/thymidine phosphorylase (PD-ECGF/TP), tumour necrosis growth factors and vascular endothelial growth factor (VEGF). Their role in the proliferation and migration of endothelial cells from pre-existing vessels is described, concentrating on VGEF and its receptors (VEG-R1 and -R2), and the fibroblast growth factor (FGF) family. The actions of the products of the VEGF gene are outlined, and the hormonal and non-hormonal control of their localization in the human endometrium and biological actions on vasculature and coagulation are described. Finally, the role of VEGF in menorrhagia is assessed.     

Endocrinology and paracrinology: The presence of platelet-derived endothelial cell growth factor in human endometrium and its characteristic expression during the menstrual cycle and early gestational period

Decidualized tissues are characterized by the intensive outgrowthof the microvasculature. Several angiogenic factors are assumedto be involved during the drastic change in the vasculatureoccurring in the process of decidualization. We examined thepossible role of platelet-derived endothelial cell growth factor(PD-ECGF), a known angiogenic factor, during the process ofearly decidualization in humans. The expression of PD-ECGF inhuman endometrium was demonstrated by Western blot analysis,a marked increase being found in decidualized endometrium. Immunohistochemicalstaining showed that PD-ECGF immunoreactivity was present mainlyin decidualized endometrial stromal cells. We established aprimary cell culture of human endometrial stromal cells whichwere differentiated into decidualized cells in vitro by theaddition of progesterone. In this cell culture system, progesteroneaugmented the expression of PD-ECGF in a dose-dependent fashion.The addition of progesterone also resulted in an increased releaseof prolactin, a well-known marker for decidualization. Thesefindings suggest that PD-ECGF may play a physiological roleas a possible angiogenic factor in the process of decidualizationof human endometrium.     

Focal vascular endothelial growth factor correlates with angiogenesis in human endometrium. Role of intravascular neutrophils

Vascular endothelial growth factor (VEGF) is expressed in human endometrium, but the cellular source of VEGF for endometrial angiogenesis has not been determined. In the present study the relationship between focal VEGF associated with microvessels and endothelial cell proliferation was examined in three layers of human endometrium at various stages of the menstrual cycle (menstrual, proliferative and secretory). Immunohistochemical analysis of full thickness endometrium from 18 hysterectomy samples without endometrial pathology were examined. The percentage of proliferating vessels was higher in proliferative compared to secretory endometrium, but this was only statistically significant in the basalis layer. A significantly greater percentage of VEGF-expressing microvessels was observed in proliferative than secretory endometrium (P < 0.05). The most VEGF-expressing microvessels were observed in the subepithelial capillary plexus, followed by the functionalis and least were present in the basalis. There was a significant correlation between focal VEGF-expressing microvessels and proliferating vessels for the subepithelial capillary plexus (R(s) = 0.70, P = 0.008), the functionalis (R(s) = 0.70, P = 0.001) and the basalis (R(s) = 0.76, P < 0.001). Focal VEGF associated with microvessels was found in marginating and adherent neutrophils. These data suggest that neutrophils in intimate contact with endometrial endothelium may be a source of intravascular VEGF for vessels undergoing angiogenesis by elongation or intussusception, particularly during the proliferative phase of rapid endometrial growth.     

Endometriosis: Immunohistochemical analysis of oestrogen and progesterone receptors in endometriotic tissue and endometrium

The objective of the study was to compare the localization andstaining intensity of oestrogen and progesterone receptors inendometrium and endometriotic tissue. Using monoclonal antibodiestowards oestrogen and progesterone receptors, analysis was performedin 63 endometriotic samples from 40 women and compared to endometriumobtained simultaneously from 25 of the women. Using a stainingindex, ‘total immuno-staining score’, calculatedfrom the staining intensity multiplied by the fraction of positivecells, the receptor content was estimated semiquantitatively.The scores for both oestrogen and progesterone receptors werelower in endometriotic epithelial cells than in endometrialepithelial cells, but the differences reached statistical significanceonly for the progesterone receptor. No difference was foundfor stromal cells. There was a significant correlation betweenoestrogen receptor score in endometriotic tissue and in endometrium,but not for progesterone receptor score. In endometrium andvaginal and peritoneal endometriosis, the progesterone receptorscore showed similar values, higher than those in ovarian endometriosis.The data from this large immuno-histochemical study supportprevious results of quantitative steroid receptor analyses,indicating that the regulation of steroid effects, especiallythose of progesterone, differs between endometriotic and endometrialtissue.     

Expression of vascular endothelial growth factors and their receptors in human endometrium from women experiencing abnormal bleeding patterns after prolonged use of a levonorgestrel-releasing intrauterine system

BACKGROUND: Menstrual bleeding disturbances are a common initial complaint among users of the levonorgestrel-releasing intrauterine system (LNG-IUS). In this study, women who experienced bleeding disturbances recurring after a previous period of problem-free use and who therefore wanted removal of their LNG-IUD were investigated. Vascular endothelial growth factors (VEGFs) and their receptors are thought to be involved in normal endometrial angiogenesis. The aim of the study was to elucidate the possible association of these VEGF and receptors with bleeding disturbances among users of LNG-IUS. METHODS: Endometrial biopsies were obtained from users of the LNG-IUS who complained of bleeding disturbances (n = 17) and from women without such problems (n = 14). The endometrial expression of these VEGFs and their receptors was analysed using immunohistochemistry. RESULTS: Endometrial endothelial cells from LNG-IUS users with menstrual bleeding disturbances exhibited significantly higher immunoreactivity for VEGFR-1 and VEGFR-3 than those from women without bleeding disturbances. Stromal cells showed significantly lower immunoreactivity for VEGF-A in samples from LNG-IUS users with bleeding disturbances than in those without. CONCLUSION: Changes in the expression of these angiogenic growth factors and their receptors in LNG-IUS-exposed endometrium might be involved in the formation of fragile and dysfunctional blood vessels that subsequently give rise to bleeding disturbances.     

Uterus and endometrium: Endometrial vascular smooth muscle oestrogen and progesterone receptor distribution in women with and without menorrhagia

This study tested the hypothesis that alterations in the expressionof oestrogen and progesterone receptors (ER and PR) in endometrialvascular smooth musde cells (VSMC) may play a role in the increasedblood loss that occurs during menorrhagla. Subject groups were:controls (n±40), those with menorrhagia (menstrual bloodloss >80 ml, n±39) and patients post-endometrial ablation(n±16). The aims of our study were to describe the changingdistribution of VSMC ER and PR during the menstrual cycle andto look for differences between the three groups. Immunohistochemicaldouble-staining results for VSMC and either ER or PR were highlyvaried, with 0–85% of endometrial arterioles in a biopsysection having alpha smooth muscle actinlER positive cells,and 0–70% demonstrating PR. There were no significantdifferences between controls, menorrhagia or post-ablation specimens(analysis of variance for ER P±0.72; for PR P±0.17).There were also no significant differences between the differentstages of the menstrual cycle when all three groups were combined(analysis of variance for ER P±0.11; for PR P±0.13).The high variability found in this study may mask biologicallyrelevant differences in endometrial vascular ER and PR distributionbetween different groups.     

Physiology: Effects of the pure anti-oestrogen ICI 182780 on oestrogen receptors, progesterone receptors and Ki67 antigen in human endometrium in vivo

The new steroidal pure anti-oestrogen ICI 182780 was studiedfor the first time in pre-menopausal women. A total of 30 patientsrequiring hysterectomy for benign gynaecological disease wererandomized to ICI 182780, 12 mg/day i.m. (n = 19) or no treatment(n = 11) for 7 days prior to surgery. Immunohistochemical measurementswere made in the snap-frozen, resected endometrium for oestrogenreceptors (ER), progesterone receptors (PgR) and Ki67, a nuclearantigen whose expression is closely related to proliferation.Five control patients ovulated prior to surgery and, as expected,the secretory endometria had lower Ki67 antigen concentrationsthan endometria from the proliferative phase. The endometriafrom patients treated with ICI 182780 had reduced Ki67 comparedwith controls. This demonstration of reduced proliferative activityindicates that the pharmacological effectiveness of the treatmentwas maintained despite increased plasma oestradiol concentrations.In contrast to results from rodents, ICI 182780 did not markedlyreduce ER expression, although there was significantly lowerER in the myometrial cells of the treated group. The lack ofeffect on PgR shows a dissociation between the drug's effecton this oestrogendependent protein and its effects on proliferation.     

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 a levonorgestrel-releasing intrauterine device on human endometrial oestrogen and progesterone receptors after one year of use

Thirty-four women bearing a levonorgestrel-releasing intrauterine device, 20 micrograms/day (LNG-IUD-20), for 12-15 months were recruited. Endometrial biopsies were collected during the late proliferative phase of the cycle (on cycle days 10-12) before (control) and after the use of the IUD for 12 months, and assayed for oestrogen receptors (ER) and progesterone receptors (PR). An immunohistochemical technique with the peroxidase-antiperoxidase detection system (PAP method) was employed. D75 and JZB39 were the primary antibodies for ER and PR respectively. The immunostaining semiquantitative analysis was performed with a computerized microscope image processor, and expressed as 'grey value'. Both endometrial ER and PR populations were significantly lower after insertion of the IUD (P < 0.01) than in control biopsies. The intensity of nuclear staining and the percentage of positively stained cells for ER and PR in women with LNG-IUD were each about 50% of those in control biopsies. The results suggested that LNG released locally from the IUD has a depressive action on the ER and PR, which may contribute to the contraceptive effectiveness of this type of IUD and also to the possible causes of LNG-IUD-induced irregular bleeding and amenorrhoea.     

Non-competitive anti-oestrogemc actions of progesterone antagonists in primate endometrium: enhancement of oestrogen and progesterone receptors with blockade of post-receptor proliferative mechanisms

Previous studies have shown that the progesterone antagonists(antiprogestins) inhibit oestrogen-dependent endometrial proliferationin ovariectomized monkeys, without having affinity to the oestrogenreceptor (ER). This study was designed to investigate the effectsof the antiprogestins mifepristone (RU 486) and onapristone(ZK 98,299), on the concentration of ER and progesterone receptor(PR) in the endometrium of long-term ovariectomized cynomolgusmonkeys (Macaca fascicularis). In untreated monkeys, tissuepreparations bound in total 228±68 pmol [³H]-oestradiol/gprotein (ER), and 119±42 pmol [³H]-R5020/g protein (PR).These values were not significantly different from the totalbinding capacities of tissues from monkeys treated with RU 486alone or primates treated with oestradiol plus progesterone.Treatment with oestradiol alone almost doubled the ER and PRconcentrations. Combined treatment with oestradiol and RU 486enhanced the ER and PR concentrations in a dose-dependent manner:1 mg/kg body weight (bw) RU 486/kg increased both ER and PRcontents about 3-fold. The dose of 5 mg/kg bw RU 486 or onapristoneincreased the ER and PR concentrations almost 6- and 5-foldrespectively, compared with the oestradiol-treated controls.Our results demonstrate that RU 486 and onapristone increasedthe endometrial ER and PR concentrations far beyond the physiologicallevel in ovariectomized, oestradiol-treated monkeys. Whetherthe over-expression of ER and PR in the presence of antiprogestinsis causally related to the antiproliferative impact of antiprogestinsin the endometrium (non-competitive anti-oestrogenic effects)or is an independent action is unknown.     

Variant progesterone receptor mRNAs are co-expressed with the wild-type progesterone receptor mRNA in human endometrium during all phases of the menstrual cycle

Progesterone receptor (PR) variant mRNAs in human endometrium could encode proteins with the potential to alter progesterone action in states of normal and abnormal endometrial development. We have assessed the expression levels of mRNA for the wild-type PR and splice variants of PR mRNA lacking exon 4 (del-4 PR), exon 6 (del-6 PR), exons 4 and 6 (del-4&6 PR), and part of exon 4 (del-p4 PR) or part of exon 6 (del-p6 PR) in the human endometrium throughout menstrual cycle development. Eighty-eight endometrial specimens (47 proliferative, 41 secretory) were collected from patients undergoing hysterectomy for benign gynaecologic causes. Measurements by RT-PCR indicated that mRNAs for wild-type PR, and splice variants del-4 PR, del-6 PR, del-4&6 PR, del-p6 PR, and a novel del-p4 PR were detected in all endometrial specimens throughout the menstrual cycle. Higher levels of wild-type PR and all PR variant mRNAs were found in the early and mid-proliferative endometrial phases than in secretory endometrium. The relative expression of mRNA for all PR variants compared to wild-type PR mRNA, however, did not change through all stages of endometrial development. We, therefore, found no evidence of differential co-expression of the PR variants compared with wild-type PR during normal menstrual development. Future studies will determine if the expression profile of PR variant mRNAs will be different in the endometrium of patients with infertility, recurrent pregnancy loss, or endometrial adenocarcinoma.     

Morphometric, immunohistological and threedimensional evaluation of the endometrium of menopausal women treated by oestrogen and Crinone, a new slow-release vaginal progesterone

Recently advanced computerized technology was applied to theinvestigation of morphometric, immunohistological and three-dimensionalchanges of the endometrial mucosa in order to evaluate quantitativelythe effects of three doses of a new slow-release vaginal progesteroneon the endometrium in post-menopausal women. A total of 20 menopausalwomen, deprived of ovarian function, were given oestrogen for12 days and a combined therapy of oestrogen (administered orally)and progesterone for another 12 day period. Progesterone wasadministered vaginally through a new gel (Crinone®) utilizinga bioadhesive, biocompatible polymer as a base to achieve asustained release effect An endometrial biopsy was taken beforetreatment, after oestrogen-only treatment and after the oestro-progestogentherapy. Before treatment, all the patients exhibited an atrophicendometrium. After oestrogen-only treatment, typical proliferativechanges occurred: an increase in the endometrium thickness,an increase in the mitotic index, numerous cylinder-like glandsand no coiled glands, and high concentrations of oestrogen receptors(ER) and progesterone receptors (PR). After the oestro-progestogentherapy, whatever the dose of progesterone given, a secretorytransformation of the endometrial mucosa occurred, mitotic activitydecreased significantly, more ramified and coiled glands wereobserved, and a decrease in PR content was noted in epithelialand stromal nuclei, and a decrease in PR content was also observedin epithelial nuclei but not in stromal nuclei. Accurate newtechniques of image analysis have shown that crinone therapycould eliminate the proliferative effects of oestrogen treatmentin post-menopausal women, despite doses as low as 45 mg of progesteroneadministered vaginally every other day. The results suggestthat the sustained release effects of Crinone are clinicallyrelevant     

Evaluation of oestrogen and progesterone receptor expression in uterine mucosal lymphocytes

Expression of the oestrogen and progesterone receptors on uterinemueosal leukocytes has been examined by dual immunohistology.Neither the oestrogen receptor nor the progesterone receptorwas expressed by lymphocytes, macrophages or the distinctivepopulation of uterine natural killer (NK) cells. Although theaccumulation and survival of these NK cells appears to be hormonallydependent, the effects must therefore be indirect.     

Expression of an oestrogen receptor-related antigen in human endometrium: a microphotometric study.

The expression of an oestrogen receptor-related antigen has been measured by microspectrophotometry in the glandular epithelium and stroma of tissue sections from endometrial biopsies of women administered exogenous replacement of sex steroids because of premature ovarian failure. We have demonstrated that previously dormant endometrium is capable of expressing an antigen related to oestrogen receptors and that its distribution is influenced by the sex steroid environment. Immunohistochemical staining was more intense (P less than 0.001) in the glandular compared to the stromal cells in tissue exposed solely to oestradiol. With the administration of progesterone, the stromal staining intensity increased (P less than 0.0001) and that of the glandular staining decreased (P less than 0.0001). No assumption, however, has been made to infer that colour is stoichiometrically related to the concentration of antigen present. Further validation of immunohistochemical procedures is required because histological localization and measurement of immunohistochemical staining may be straightforward, but its relationship to antigen concentration remains unproven.     

The effect of RU 486 administered during the early luteal phase on bleeding pattern, hormonal parameters and endometrium

The purpose of the present study was to investigate the effect of a single dose of RU 486 administered very early in the secretory phase on endometrial development and levels of progesterone receptors, on plasma levels of gonadotrophins and ovarian hormones and on the pattern of menstrual bleeding. Twenty-four regularly menstruating subjects participated and were studied during a control, a treatment and a follow-up cycle. In the treatment cycle, a single dose of 200 mg RU 486 was given in the evening of the second day after the urinary LH peak. Plasma was collected from cycle day 10 until menstruation in both control and treatment cycles. The lengths of the control, treatment and follow-up cycles were equal. Three of the subjects had slight vaginal bleeding in association with RU 486 intake which, however, did not disturb their normal menstrual rhythm. Plasma levels of oestradiol, progesterone and FSH were not affected in the treatment cycle, whereas LH levels increased slightly. The elimination half-life of RU 486 was 28.6 h. An endometrial biopsy was taken 12, 36 or 84 h (LH + 3, LH + 4 and LH + 6) after drug intake (eight subjects in each group) and another biopsy was taken on the corresponding day in the control cycle. The specimens were assessed by morphometric analysis and for cytosolic progesterone receptor concentrations. Endometrial biopsies taken 12 h (on LH + 3) after RU 486 intake contained significantly (P less than 0.001) lower levels of cytosolic progesterone receptors than in the control cycle, but levels at 36 and 84 h were similar.(ABSTRACT TRUNCATED AT 250 WORDS)