Disease relevance of Myometrium

• An oligonucleotide probe constructed by the cDNA of the hcrp gene that encodes this aa sequence depicted the expression of 1.9-kb LDGF mRNA in leiomyomas and myometrium [1].
• The patient's IgG fraction, containing the lupus anticoagulant, reduced the release of prostacyclin (PGI2) from rat aorta rings or pregnant human myometrium [2].
• In malignancies of the uterus, we find that ZEB1 (a) is overexpressed in malignant tumors derived from the myometrium (leiomyosarcomas), (b) is overexpressed in tumor-associated stroma of low-grade endometrioid adenocarcinomas, and (c) is aberrantly expressed in the tumor epithelial cells of aggressive endometrial cancers [3].
• Electrofocusing and sucrose density gradient analysis confirmed that D5 antigen is a non-hormone-binding component related to cytosolic RE from breast tumor and myometrium [4].
• In the guinea pig myometrium, carbachol, oxytocin, and fluoroaluminates stimulated the breakdown of phosphatidylinositol 4,5-bisphosphate, which was insensitive to pertussis toxin [Biochem. J. 255:705-713 (1988)] [5].

Psychiatry related information on Myometrium

• Other mechanisms of possible importance such as ovarian hormones, cervical factors, vasopressin, nerves, and psychological factors can well act ultimately through prostaglandin release but an action directly on the myometrium and blood flow may also occur [6].

High impact information on Myometrium

• The hormone relaxin has recently been shown to inhibit not only uterine muscle contraction, but also the release of oxytocin into the plasma [7].
• At this time high titres of relaxin are present in the plasma and there is evidence that the hormone has a direct inhibitory action on the uterine muscle [8].
• In vitro, prostaglandin production by the decidua, but not by the myometrium, was increased by the addition of oxytocin [9].
• Cardiac glycosides that are known to exert estrogen-like effects on classical estrogen target tissues, such as uterine muscle, endometrium, vagina, and mammary gland, probably act on atrial muscle through a genomic, steroid hormone-like mechanism of action [10].
• We conclude that increased CGRP-Rs in myometrium, and resulting enhanced myometrial sensitivity to CGRP, may play a role in maintaining human myometrium in a quiescent state during pregnancy, and that a decline in the CGRP-Rs at term could contribute to the initiation of labor [11].

Chemical compound and disease context of Myometrium

• Cytosolic fractions from leiomyoma homogenate displayed 5-fold higher activity (estrone to estradiol), compared with surrounding myometrium (n = 6, P < 0.05), whereas microsomal fractions showed no difference [12].
• Apparently, high progesterone levels down-regulate the ER in both fibroids and myometrium, whereas estrogen mediates the up-regulation of the PR during the proliferative phase [13].
• We found that rapid chilling of tissue at surgery was necessary to maintain specific progestin binding in myometrium, that leupeptin permitted demonstration of 8S receptors in myometrium and leiomyoma, and that 8S receptors were present in endometrium, with or without leupeptin [14].
• Expression of 17beta-hydroxysteroid dehydrogenases (17beta-HSDs) was compared between leiomyoma and myometrium [12].
• Hypothyroidism reduced the increase in the mitotic index 5-fold in the luminal epithelium, 6-fold in the stroma, and 9-fold in the myometrium [15].

Biological context of Myometrium

• The demonstration that endothelin (ET) induces rat uterine contraction, coupled with the observation that ET is present in human amniotic fluid, suggests that the myometrium may be an important target organ for this hormone [16].
• Cyclo-oxygenase-type-2 (COX-2) enzyme is fundamental for nephrogenesis, upregulated on fetal membranes and myometrium at parturition [17].
• Hmx3 is one of the earliest markers for vestibular inner ear development during embryogenesis, and is also upregulated in the myometrium of the uterus during pregnancy [18].
• These findings verify that multiple isoforms of the maxi-K channel are present in the mouse myometrium and are regulated differentially during gestation, which is a likely mechanism for modulation of myometrial excitability during pregnancy [19].
• Up-regulation of the progesterone receptor (PR)-C isoform in laboring myometrium by activation of nuclear factor-kappaB may contribute to the onset of labor through inhibition of PR function [20].

Anatomical context of Myometrium

• This study clearly demonstrates the expression of HO in the human myometrium and shows that its induction produces CO that limits uterine contractility in pregnant myometrium indicating a role for the HO-CO-cGMP pathway in the maintenance of the quiescent state of the uterus during pregnancy [21].
• We found that iNOS is expressed in smooth muscle cells of pregnant myometrium [22].
• In contrast, renin mRNA expression was not detected in basal plate and intertwin chorion (which is separate from decidua), amnion, myometrium, or placental villi [23].
• In summary, iNOS expression in the myocytes of human myometrium is increased greatly during pregnancy, and declines towards term or with labor [22].
• PTHrP mRNA was identified by Northern analysis as a single species (approximately 1.8 kilobases) in human amnion, chorion, placenta, decidua, and myometrium [24].

Associations of Myometrium with chemical compounds

• The progesterone-induced decrease in the number of uterine alpha adrenergic receptors provides a potential explanation for the reduced alpha adrenergic contractile response to epinephrine in the progesterone-primed myometrium [25].
• SR 49059 showed high affinity for V1a receptors from rat liver (Ki = 1.6 +/- 0.2) and human platelets, adrenals, and myometrium (Ki ranging from 1.1 to 6.3 nM) [26].
• Prostaglandin E2 receptors (EP) were detected by radioligand binding in nuclear fractions isolated from porcine brain and myometrium [27].
• Electrophysiological study of the action of angiotensin II on the rat myometrium [28].
• The accompanying electrophysiological changes were measured on strips of rat myometrium at 35 degrees C using the double sucrose-gap technique [28].

Gene context of Myometrium

• The biological actions of corticotropin-releasing hormone (CRH) in the human myometrium during pregnancy and labor are unknown [29].
• A novel spliced variant of the type 1 corticotropin-releasing hormone receptor with a deletion in the seventh transmembrane domain present in the human pregnant term myometrium and fetal membranes [30].
• We therefore hypothesized that activation of MAPK might mediate CRH and or/urocortin actions in the myometrium [31].
• We have now investigated the expression of Cox-2 in human myometrium [32].
• These data demonstrate physiological regulation of TrpC mRNA and protein and suggest an important role for TrpC proteins in human myometrium during labor [33].

Analytical, diagnostic and therapeutic context of Myometrium

• Mice were immunized with 1 to 3 micrograms of cytoplasmic estrogen receptor fragment purified from human myometrium by affinity chromatography [4].
• alpha 2A- and alpha 2B-adrenoreceptors (AR), identified by Northern blotting in rat myometrium, showed a differential expression during the course of pregnancy [34].
• We identified CRH receptors in myometrium and FM by semiquantitative RT-PCR and immunohistochemistry [35].
• Quantification of messenger ribonucleic acid for epidermal growth factor in human myometrium and leiomyomata using reverse transcriptase polymerase chain reaction [36].
• Western blot analysis showed a band at 41 kDa in endometrium and myometrium, confirming the presence of 11 beta HSD2 [37].

References