PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Myometrium”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1988

The significance of prostacyclin produced by pregnant rat myometrium: the relationship between myometrial prostacyclin producing activity and passive stretch of myometrium by growing conceptus.

The present experiment was performed to elucidate the significance of prostacyclin (PGI2) produced by pregnant rat myometrium. PGI2-like substance producing activity of various portions of the uterus was measured at selected gestational stages by platelet bioassay; surface area per 1 gm of uterine wall enveloping one conceptus was calculated; and spontaneous contractility of myometrium of both conceptus and non-conceptus regions and the effects of authentic PGI2 on it were examined. PGI2-like substance producing activity increased with advancing pregnancy, but the activity varied according to area of the myometrium, being highest in the area where it was most greatly stretched by the growing conceptus and lowest where no conceptus was contained. Spontaneous contractility was reduced in regions with high PGI2 producing activity. Though authentic PGI2 generally exhibited a stimulatory effect, it had an inhibitory effect on Day 10 pregnant myometrium. From these results, it may be concluded that the producing activity of PGI2, which remarkably increases in the conceptus region with the advance of pregnancy, keeps the uterine wall relaxed, making the uterus adapt to the growth of the fetus. Passive myometrial stretch by the growing conceptus is thought to be one of factors which enhance myometrial PGI2 producing activity.

Animals↗
PubMed2025

Transcriptomics and proteomics reveal associations between myometrium and intrauterine adhesions.

BACKGROUND: Intrauterine adhesions (IUAs) is a gynecological condition with a poor therapeutic prognosis, that severely threatens the fertility and the reproductive physiology and psychological health of women. Our previous research on the use of umbilical cord mesenchymal stem cells (HUCMSCs) for treating IUAs revealed that CM-Dil-labelled HUCMSCs were barely distributed in the endometrial epithelium. Instead, these cells were predominantly found in the myometrium, with no statistically significant difference in distribution compared to the endometrial stromal cells. Therefore, we aimed to explore the associations between the myometrium and IUAs. METHODS: Eight patients with moderate and 5 severe lesional IUAs were included in the experimental group. The control group included 7 patients whose inner and outer myometrium were normal. We used H&E, Masson's trichrome and immunohistochemical staining to obtain the pathological features of the tissues. Transcriptomic and proteomic analyses were conducted to identify differentially expressed genes, proteins and enrichment pathways. RESULTS: Both IUAs lesion tissues expressed the smooth muscle markers &#x3b1;-SMA and H-caldesmon, and there was no significant difference between severe IUAs tissue and normal myometrium (p&#x2009;>&#x2009;0.05). Transcriptomic and proteomic data revealed that genes and proteins involved in cell mitosis, such as KIF14, KIF4A, and CIT, were downregulated in both IUAs lesion tissues compared with the inner myometrium (p&#x2009;<&#x2009;0.05). Additionally, some genes or proteins that participate in activating the complement-coagulation cascade system and extracellular matrix (ECM) degradation also significantly differed (p&#x2009;<&#x2009;0.05). CONCLUSIONS: Transcriptomic and proteomic data revealed a correlation between endometrial injury and the myometrium. These findings preliminarily revealed that the myometrium possibly contributes to the aetiology and progression of IUAs through dual mechanisms. On the one hand, the myometrium inhibits endometrial regeneration by suppressing the cell mitogenic pathway. On the other hand, it promotes fibrosis by activating the complement-coagulation cascade system and inhibiting the ECM degradation pathway. These new findings increase our understanding of the pathogenesis of IUAs and potentially contribute to the application of precision clinical treatment for IUAs.

Humans↗
PubMed1987

Enzymology of human myometrium: variations related to the hormonal milieu.

The activities of various enzymes involved in glycolysis, tricarboxylic acid cycle and fatty acid oxidation were assayed in human myometrium. A gradient of the activities from fundal to cervical myometrium was observed. In contrast to studies performed in rodents, cyclic changes of glycolytic enzymes could not be detected. Hydroxyacyl-CoA-dehydrogenase (HAD) activity was higher in secretory phase myometrium and in cases with cystic hyperplasia of the endometrium than in proliferative phase myometrium. In pregnant myometrium, lactate dehydrogenase (LDH) and glycogen phosphorylase (GLP) were increased and in postmenopausal myometrium the activities of phosphofructokinase (PFK), LDH and succinate dehydrogenase (SDH) were decreased as compared to proliferative phase myometrium. We conclude that in the human myometrium, except for HAD, activities of enzymes involved in fuel metabolism are stable throughout the menstrual cycle and that only prolonged hormonal stimulation leads to alterations of some enzyme activities.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1985

Prostaglandin E and F2 alpha receptors in human myometrium during the menstrual cycle and in pregnancy and labor.

The binding of prostaglandins E1 and F2 alpha has been studied in the human myometrium and cervix during the menstrual cycle and in the myometrium of pregnant patients at term before and during labor. Tritium-labeled prostaglandin E1 and F2 alpha binding was saturable and reversible. Scatchard analysis of tritium-labeled prostaglandin E1 binding was linear, which suggests a single class of high-affinity binding sites with an estimated apparent equilibrium dissociation constant of 2.5 to 5.4 nmol/L and inhibitor affinities of 0.9, 273, 273, and 217 nmol/L for prostaglandins E2, A1, B1, and F2 alpha, respectively. Scatchard analysis of tritium-labeled prostaglandin F2 alpha, binding was also linear, but the affinity of these binding sites was much lower, with an average dissociation constant of 50 nmol/L and inhibitor affinities of 1.6, 2.2, and 11.2 nmol/L for prostaglandins E1, E2, and A1, respectively. In nonpregnant patients, the concentrations and affinities of tritium-labeled prostaglandin E1 binding sites were similar in the myometrium during the proliferative and secretory phases of the menstrual cycle, but the concentration of these sites was much lower in the cervix. The concentration of the tritium-labeled prostaglandin E1 binding sites was significantly lower in the myometrium of pregnant patients at term than in the myometrium of nonpregnant patients. The concentrations and affinities of tritium-labeled prostaglandin E1 binding sites were not significantly different in the upper and lower myometrium of pregnant patients at term or in the myometrium of such patients before and during labor. The concentrations of the tritium-labeled prostaglandin F2 alpha binding sites during the menstrual cycle and in pregnancy at term were similar to those of tritium-labeled prostaglandin E1 binding sites. In addition to confirming the presence of specific prostaglandin E and F2 alpha binding sites in the myometrium, these data also suggest: that specific prostaglandin E binding sites are present in the cervix and that the concentrations and affinities of prostaglandin E binding sites do not change during the menstrual cycle and are similar before and during labor in pregnant patients at term.

Cervix Uteri↗
PubMed1991

Immunohistochemical analysis of oestrogen receptors, progesterone receptors and Ki-67 in leiomyoma and myometrium during the menstrual cycle and pregnancy.

Immunohistochemical distribution of oestrogen receptors (ER), progesterone receptors (PR), and the cell proliferation-associated antigen Ki-67 was investigated in leiomyomas and the myometrium during the menstrual cycle and pregnancy. In the myometrium, ER expression was observed in the proliferative phase, but was suppressed in the secretory phase and during pregnancy. In leiomyomas, ER expression was observed throughout the menstrual cycle, but was suppressed during pregnancy. However, PR was expressed both in the myometrium and leiomyomas throughout the menstrual cycle and pregnancy. In both the myometrium and leiomyomas, a higher number of Ki-67-positive cells was observed during pregnancy than in the secretory phase, and Ki-67 was negative during menopause. The Ki-67-positive cell count in leiomyomas was significantly higher than that in the myometrium throughout the menstrual cycle and pregnancy. Thus both myometrium and leiomyomas have high growth activity under the hormonal milieu of high progesterone levels. The growth potential of leiomyomas is apparently higher than that of myometrium throughout the menstrual cycle and during pregnancy.

Adult↗
PubMed1994

Differential expression of mRNAs for endothelin-related proteins in human endometrium, myometrium and leiomyoma.

The expression of mRNAs encoding endothelin-1 (ET-1) and its receptors (ETA-R and ETB-R) as well as the ET degrading enzyme, neutral endopeptidase 24.11 (NEP), was determined in tissue samples of endometrium, myometrium and leiomyoma by using a reverse transcriptase polymerase chain reaction (RT-PCR) technique. ET-1 mRNA was detected in all samples studied. The level of ET-1 mRNA was higher in endometrium than in myometrium (p < 0.01) and leiomyoma (p < 0.001). The ETA-R mRNA was more abundant in endometrium than in myometrium (p < 0.001). For ETB-R mRNA there was no difference between these tissues. In contrast to ETA-R mRNA, which was more abundant in leiomyoma than in myometrium (p < 0.01), the ETB-R mRNA was less abundant in leiomyoma (p < 0.01). The NEP mRNA was detected in all endometrial samples but not in myometrium and leiomyoma. Our results show that the expression and relative levels of mRNAs encoding ET-1, ETA-R, ETB-R, and NEP vary in different tissue compartments of the human uterus. Since the net biological action of ET-1 in a particular cell type presumably depends on the balance between the peptide itself, its receptors and degrading enzymes, these results suggest different roles for ET-1 action in uterine endometrium, myometrium and leiomyoma. The difference in relative abundance of ETA-R and ETB-R mRNAs between myometrium and leiomyoma suggests that an altered ET-R gene expression may be a contributing factor in myomal growth.

Base Sequence↗
PubMed1996

C-fos and c-jun expression in human endometrium and myometrium.

Estrogen is a mitogen in human endometrium and is considered to be responsible also for myometrial cell proliferation. Signalling pathways of estrogen action in these tissues are not known. In various other estrogen responsive cells, estrogen induces transient expressions of c-fos and c-jun mRNAs. We examined c-fos and c-jun mRNA expressions by Northern blotting in paired samples of endometrium, myometrium and leiomyoma tissues obtained from women under various hormonal environments as well as of endometrium and myometrium at term pregnancy. In nonpregnant endometria, strong expressions of c-fos (2.2 kb) and of c-jun (2.7 kb and 3.2 kb) were detected both in the follicular and luteal phase of the menstrual cycle, and the c-fos expression was significantly stronger in proliferative phase endometrium than in the adjacent myometrium. In most of the myometrial and leiomyoma tissue samples the signals for both protooncogenes were weak, and there were no systematic differences in the expressions between normal myometrium and myomatous tissue. In pregnant endometrium and myometrium, both the c-fos and c-jun mRNA expressions were nearly undetectable, and in pregnant endometrium expressions were significantly lower than those in nonpregnant endometrium. Also in late pregnancy myometria, the expression of c-jun was significantly lower than in nonpregnant tissues. These data suggest that c-fos and c-jun activation may be a part of estrogen-induced signal transduction in the endometrium, and that in term pregnancy endometrium this signalling pathway is inhibited. Due to the strong expression of c-jun and c-fos both in the proliferative and secretory phase endometrium, it is likely that these protooncogenes are related to functions other than epithelial cell proliferation in human endometrium. The weak expressions of c-fos and c-jun in the myometrium and in leiomyomata suggest that signalling pathways mediating steroid hormone action in endometrium and myometrium are different.

Adult↗
PubMed1991

The gene expressions of macrophage colony-stimulating factor (MCSF) and MCSF receptor in the human myometrium during pregnancy: regulation by sex steroid hormones.

We investigated the biological effect of sex-steroid hormones, secreted from the corpus luteum and placenta, on the induction of mRNA encoding macrophage colony-stimulating factor (MCSF) and c-fms proto-oncogene (MCSF receptor) in the human uterine myometrium. Poly(A)+RNA was extracted from the myometrium of pregnant and non-pregnant uterine myometrium and then Northern blot analysis was performed on poly(A)+RNA. The myometrium of non-pregnant women expressed neither mRNA of macrophage colony-stimulating factor (MCSF) nor any transcript related to the c-fms proto-oncogene. On the other hand the myometrium of pregnant women expressed MCSF mRNA (4.7 kb) and two kinds of transcript related to the c-fms proto-oncogene (3.9 and 1.3 kb). The mRNAs of both MCSF and c-fms proto-oncogene were induced in the uterine myometrium of non-pregnant women under pseudopregnant therapy of mestranol and norethindrone. These results indicate that sex steroid hormone secreted from the corpus luteum of pregnancy and/or placenta may be deeply involved in the hypertrophic change of uterus during pregnancy by inducing MCSF and MCSF receptor (c-fms proto-oncogene protein product) in the myometrium.

Corpus Luteum↗
PubMed1984

Estrogen and progesterone receptor and hormone levels in human myometrium and placenta in term pregnancy.

Estradiol and progesterone receptors in the myometrium, decidua, placenta, chorion, and amnion of eight women who underwent elective cesarean section at term were determined by means of an exchange assay. The hormone levels in the peripheral plasma and cytosol of these tissues were measured by radioimmunoassays. Maternal plasma and the placenta had high concentrations of estradiol and progesterone, with the placenta having 12 times more progesterone than in maternal plasma but only half the concentrations of estradiol in maternal plasma. The decidua and placenta had detectable levels of cytosol and nuclear estradiol receptors, but the myometrium had no measurable cytosol estradiol receptors, whereas the chorion and amnion had neither cytosol nor nuclear estradiol receptors. However, the chorion and amnion had significantly higher concentrations of estradiol in the cytosol than those in the decidua and myometrium. Only the decidua and myometrium had cytosol and nuclear progesterone receptors, but the placenta, amnion, and chorion had neither cytosol nor nuclear progesterone receptors. In contrast, progesterone hormone levels were significantly higher in the placenta, amnion, and chorion than in the decidua and myometrium. The findings indicate that, in the term pregnant uterus, (1) the placenta, amnion, and chorion are rich in progesterone, estradiol, and nuclear estradiol receptors but have no progesterone receptors, (2) the decidua and myometrium have nuclear estradiol and progesterone receptors, and (3) the myometrium has a higher progesterone/estradiol ratio than that of the peripheral plasma, thus suggesting a highly progesterone-dominated uterus.

Amnion↗
PubMed1995

Increased sensitivity of rat myometrium to the contractile effect of platelet activating factor before delivery.

1. The contractile effects of platelet activating factor (PAF) were compared in the myometrium isolated from non-pregnant and pregnant rats. 2. In the non-pregnant myometrium, PAF, at a concentration of 0.1 microM, did not change muscle tension and induced only a small transient contraction at 10 microM. 3. The contractile responses to PAF increased with the progress of gestation. In the late pregnant myometrium (21 day after gestation), PAF (0.1 nM-10 microM) induced large and relatively sustained contractions. The threshold concentration of PAF was decreased by approximately 10,000 times and the maximum contraction was increased 5 times by day 21 of gestation. 4. PAF (10 microM) increased the cytosolic Ca2+ concentration ([Ca2+]i) and muscle contraction to levels higher than those induced by high K+ in the pregnant rat myometrium (day 21). Verapamil (10 microM), a voltage-dependent Ca2+ channel blocker, decreased the stimulated [Ca2+]i and muscle tension to 49.6% and 22.7%, respectively, while the same concentration of verapamil completely inhibited the high K(+)-induced responses. 5. PAF (10 microM) induced a transient increase in [Ca2+]i with no contraction in the absence of external Ca2+ in the pregnant myometrium (day 21). 6. These results suggest that PAF induces contraction in rat myometrium by increasing Ca2+ influx. Although PAF released Ca2+ from stored sites, this Ca2+ does not seem to contribute to the PAF-induced contraction. Our major finding is that the sensitivity of the myometrium to PAF increased after gestation and that this may play a role in delivery.

Animals↗
PubMed1979

Beta-adrenoceptors in the pregnant and non-pregnant myometrium of the goat and cow.

The muscle relaxing effect of beta-adrenoceptor agonists was examined without and with the presence of beta-adrenoceptor antagonists in strips from the pregnant and non-pregnant myometrium of the goat and from the pregnant myometrium of the cow. Isoprenaline, salbutamol and ritodrine caused a dose-dependent reduction of the spontaneous contractions of the pregnant myometrium and a dose-related and parallel shift to the right of the isoprenaline dose-response curve was obtained with butoxamine but not with practolol. Isoprenaline but neither salbutamol nor ritodrine caused a dose-related reduction of the spontaneous contractions in the non-pregnant myometrium and a dose-related and parallel shift to the right of the dose-response curve of isoprenaline was brought about with propranolol but not with either butoxamine or practolol. The muscle relaxing effect of ritodrine on the pregnant myometrium of the goat and cow shown in vitro was also demonstrated in vivo in the same species within eight hours of delivery. It is concluded that the beta-adrenoceptors in the pregnant myometrium of the goat and cow belong to the beta2-group whereas those in the non-pregnant myometrium cannot be classified as either beta1- or beta2-adrenoceptors.

Albuterol↗