Search Results

Summary. The synthesis of a soluble protein (referred to as 'decidualization-associated protein', DAP), has been examined in uterine and placental tissues of rats during pregnancy by means of polyacrylamide gel electrophoretic analysis of [³H]leucine-labelled soluble proteins. No synthesis of the protein was detected in non-implantation regions of the uterus. In implantation site tissue, no synthesis was detected on Days 6 or 7 of pregnancy. Only slight synthesis was present in the endometrium on Day 8, but synthesis rose rapidly from Days 9 to 12 in both the endometrium and myometrium although differences in the rates of increase were observed. Synthesis fell from Day 12 to 14 in both tissues. Synthesis by the myometrium was entirely localized in the mesometrial region, which contains the metrial gland.

After Day 12, when the endometrium is represented by the chorioallantoic placenta, synthesis was examined in the labyrinthine and the decidua basalis/basal zone placenta tissues. No synthesis of 'DAP' was detected in the labyrinthine placenta from Day 16 of pregnancy. Synthesis observed in the decidua basalis/basal zone placenta fell dramatically from Day 14 to 20. The pattern of synthesis of 'DAP' during pregnancy suggests a role in the establishment of the chorioallantoic placenta and metrial gland in the rat.

Summary. Pregnancy-associated endometrial α₂-globulin (α₂-PEG), the major secretory protein of the human uterine endometrium during the luteal phase of the menstrual cycle and early first trimester of pregnancy, has been detected by immunochemical techniques in seminal plasma. Biochemical analysis and immunoblotting has verified that immunoreactive α₂-PEG in seminal plasma exhibits properties identical to those of endometrial α₂-PEG, i.e. Concanavalin A-binding dimeric glycoprotein of native M _r 56000, subunit M _r 28 000, average pI 4·7 and of α₂-mobility. Concentration of α₂-PEG in seminal plasma was 22·13 ± 2·82 μg/ml (mean ± s.e.m., n = 110) which compared to 12·02 ± 1 ·65 μg/ml (mean ± s.e.m., n = 48) found in amniotic fluid at 11–20 weeks of pregnancy, to 4·29 ± 1·66 μg/ml (mean ± s.e.m., n = 15) in uterine luminal fluid in women during the luteal phase and to 0·245 ± 0·025 μg/ml (mean ± s.e.m., n = 10) in sera at 10 weeks of pregnancy. This distribution is very different from that observed for pregnancy-associated placentally-derived serum proteins detected in seminal plasma. The source of α₂-PEG in seminal plasma is unknown but is unlikely to be the testis because of the normal levels observed in vasectomized men. In the endometrium α₂-PEG synthesis and secretion appears to be related to progesterone-dependent differentiation of the glandular epithelium. Therefore these observations suggest that a different mechanism of regulation of the gene for α₂-PEG operates in the male reproductive tract.

The distribution of the α₁, α₃–α₆, β₁, β₃ and β₄ integrin subunits in fetal membranes at term was examined using an indirect immunofluorescence technique and confocal laser scanning microscopy. In the amniotic epithelium, β₄ integrin (α₆β₄) exhibited distinct basal localization, whereas β₁ integrins (α₃β₁, α₅β₁) were localized basolaterally. This finding suggests that integrins, especially α₆β₄ which is a structural component of the hemidesmosomes, may function as basement membrane receptors. Integrins localized laterally may play a role in cell–cell interactions. β₁ (α₁β₁, α₅β₁) integrins are probably involved in cell–matrix interactions in the connective tissue layers which are rich in collagens and fibronectin. Cytotrophoblasts, located predominantly towards the chorionic basement membrane, mainly expressed α₆β₄, while those located predominantly in the vicinity of decidua expressed α₅β₁, α₃β₁ and α₁β₁. Decidual cells expressed α₃β₁ and α₁β₁, whereas α₁, α₅, α₆, β₁ and β₄ were expressed in blood vessels. This pattern of integrin expression reflects the reported difference in composition of the extracellular matrix at these locations and obviates an important role for α₅β₁ at the chorio–decidual interface. The differential integrin expression at the cell–basement membrane interfaces demonstrated in this study (at amniotic epithelium, cytotrophoblasts, decidual cells and blood vessels) indicated a differential recognition of basement membranes by these cells. β₄ may have a specialized function at the blood vessels, and possibly in cytotrophoblasts, that is distinct from its role in hemidesmosome-mediated attachment. This study suggests that integrins may be involved in cell–matrix and cell–cell adhesions in fetal membranes and may therefore be important for maintaining their normal structural and functional integrity.

Summary. Monoclonal and polyclonal antibodies to pregnancy-associated endometrial α₂-globulin (α₂-PEG), a glycosylated human β-lactoglobulin homologue, were used in an immunohistological technique to determine the cellular localization of this protein in the decidua and placental tissues during pregnancy. During the first trimester the protein was principally localized to the glandular epithelium of the decidua spongiosa region of the endometrium with only weak staining associated with glands of the decidualized decidua compacta region. No significant cellular staining was detected in the decidua capsularis. At term in the decidua of the amniochorion and the placental bed weak staining for α₂-PEG was only associated with the epithelium of attenuated glands. No significant staining was detected in the placenta during pregnancy. These results suggest that the epithelium of glands associated with non-decidualized stroma represents the primary source of α₂-PEG during the first trimester and that a function of the decidua spongiosa in early pregnancy may be related to production of α₂-PEG. The decline in production of α₂-PEG during pregnancy is suggested to result from involution of the decidua spongiosa and at term the attenuated glands of the decidua represents the source of α₂-PEG.

Keywords: endometrium; decidua; placenta; pregnancy-associated proteins; β-lactoglobulin homologue; man

Summary. Intrauterine instillation of heat-deaggregated glycogen in virgin mice induced a marked but transient luminal infiltration of polymorphonuclear leucocytes (PMNL). Similar injections of glycogen 2 days post coitum resulted in termination of pregnancy in the majority of treated females. Embryos recovered on Day 4 of pregnancy from the glycogen-treated females, before the expected time of implantation, had developed to the cavitated blastocyst stage, and were capable of undergoing characteristic outgrowth when cultured in vitro. A small proportion, however, appeared abnormal and did not develop in vitro. Cavitated blastocysts obtained from control mated females did not undergo outgrowth in vitro in the presence of intact PMNL, homogenates of these cells or a low molecular weight (<1500) fraction of the homogenates and after culture appeared similar to the abnormal blastocysts recovered from glycogen-treated uteri. It is proposed that the anti-fertility effect of PMNL infiltrates is due to a low molecular weight component of these cells which acts in utero and is cytotoxic to preimplantation blastocysts before their hatching from the zona pellucida.

Summary. A murine pregnancy-associated protein (α₁-PAP) with α₁-electrophoretic mobility and an estimated molecular weight of 150 000 was present in serum from pregnant C57BL/10 mice but could not be detected in serum of mature non-pregnant females and males. During pregnancy α₁-PAP was first detected on Day 7, rose to maximum levels between Days 12 and 14, and thereafter declined during the remainder of pregnancy and was undetectable by Day 8 post partum. The protein was also detected in the serum of females, but not males, subjected to an inflammatory stimulus. Examination of the α₁-PAP levels during an acute-phase response in females demonstrated that the protein behaved as a typical classical acute-phase reactant, although the levels were only 10% of those observed during Days 12 to 14 of pregnancy. α₁-PAP therefore appears to represent a hitherto undescribed female-specific acute phase reactant in the mouse.

Summary. Mouse uterine cells were obtained by trypsinization of uteri at timed intervals after the induction of a decidual reaction by intraluminal instillation of arachis oil on Day 4 of normal pregnancy. Cells were also obtained from ovariectomized mouse uteri, some of which had received a progesterone–oestradiol sequence to sensitize the uterus to a decidual stimulus. The differentiation of decidual cells was followed in cultures of these cells. The morphology of the cells obtained after 6 days in culture was dependent upon the seeding density employed. At low seeding density (plating densities of 75–100 cells/mm²) no net increase in cell number was observed, but large mononucleated stellate cells were present, with cytoplasmic and nuclear areas increased by 4-fold. At higher seeding densities (plating densities of up to 709 cells/mm²), a prolongation of cell survival and the appearance of substantial numbers of binucleated cells were observed. However, both cell types were characterized by the accumulation of filamentous material in the cytoplasm. Even at optimal seeding density the life-span of the decidualized cells could not be prolonged beyond 9 days. Uterine cells from hormone-treated ovariectomized animals underwent similar transformations but those from untreated ovariectomized mice gave only isolated islets of epithelial cells and scattered fibroblast-like cells in culture. These observations suggest that discrepancies in previous reports of in-vitro decidualization of rat uterine cells result from differences in the seeding densities employed.

Summary. During unilateral pregnancy in the guinea-pig there is loss of formaldehyde-induced fluorescence from the adrenergic nerves supplying the uterus and its vasculature. This loss occurs initially near the site of implantation at about Day 20 of gestation and spreads progressively. Implantation of wax pellets containing progesterone into the uterine lumen or the gastrocnemius muscle of virgin guinea-pigs for 7 days produced loss of fluorescence from all local adrenergic nerves. No diminution of fluorescence was seen when pellets containing oestradiol were substituted. Chronic denervation studies showed that the adrenergic axons supplying the uterus and its arteries originated from both the ovarian artery and the pelvic region. Our results suggest that loss of adrenergic fluorescence within the uterus during pregnancy is due to an effect of placental progesterone which is localized to the uterus because the high concentration of progesterone necessary to cause fluorescence loss is not attained in the systemic circulation.

A monospecific antibody was used to determine the immunocytochemical localization of insulin-like growth factor binding protein 1 (IGFBP-1) in the rat uterus. Immunoreactive IGFBP-1 was first detected from day 5 of pregnancy in the luminal and glandular epithelium. However, immunoreactivity was most intense from day 6 in the glandular epithelium, where it was associated with apically located granules. Immunoreactive glands were located only in non-decidualized endometrium, which was limited at the implant site to a thin basal layer by growth of the antimesometrial decidua from day 7. However, glands and associated immunoreactive IGFBP-1 were prominent in the inter-implant sites until day 9, although they were detected throughout pregnancy. Similar reactivity was detected in the glands of the basal endometrium in deciduomata-bearing animals, but these decreased in number from day 7 of pseudopregnancy. No immunoreactivity was detected during the oestrous cycle but could be induced in ovariectomized animals by sequential oestradiol and oestradiol plus progesterone treatment. The observations were consistent with IGFBP-1 representing a secretory product of the glandular epithelium and could either play a role in development of the trophoblastic component of the conceptus during the pre-placental period of anti-mesometrial implantation or in the endometrium acting as an inhibitor of local IGF-I action and in either case by transporting IGF-I from the stromal to the glandular luminal environment.

We used a neonatal mouse model to examine the histogenesis of uterine adenomyosis, and to test whether adenomyosis is due to an abnormality in myometrial differentiation, or in extracellular matrix proteins expression. We also studied the effects of tamoxifen and estradiol on uterine development, myometrial differentiation, and organization. Female CD1 pups were treated with oral tamoxifen (1 mg/kg) (n=27) or estradiol (0.1 mg/kg) (n=24) from age 1 to 5 days. Uteri from control (n=27) and treated mice were obtained on days 2, 5, 10, 15, and 42 of age. We examined the sections histologically, using image analysis and immunohistochemistry for α-smooth muscle actin (α-SMA), desmin, vimentin, laminin, fibronectin, and estrogen receptor-α. Following tamoxifen exposure, all uteri showed adenomyosis by 6 weeks of age (seen as early as day 10). The inner myometrium showed thinning, lack of continuity, disorganization, and bundling. α-SMA expression was normal. Desmin expression normally showed a wave of maturation that was absent in tamoxifen-treated mice. In the estradiol group, adenomyosis was not observed. All uterine layers were normally developed, but hypertrophied. The inner myometrium retained its circular arrangement. There was no difference in the localization of laminin or fibronectin between groups (laminin expression was reduced in the tamoxifen treated uteri). Vimentin could not be detected in all groups. Our results suggest that the development of the inner myometrium is particularly sensitive to estrogen antagonism, and can be affected by steroid receptors modulation. Disruption of the inner myometrium may play a role in the development of uterine adenomyosis.