Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “PLACENTAL HORMONES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

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

At least 505 records · Page 28Linked to original sources
PubMed1985

Effect of human chorionic gonadotrophin on 7,12-dimethylbenz[a]anthracene-induced DNA binding and repair synthesis by rat mammary epithelial cells.

The administration of the placental hormone human chorionic gonadotrophin (HCG) to 50-day-old virgin Sprague--Dawley rats has been shown to reduce the incidence of 7,12-dimethylbenz[a]anthracene (DMBA)-induced mammary cancer. We now report from studies using rat mammary epithelial cells in culture that the anti-carcinogenic effect of HCG may be related to its effect on DNA binding of DMBA and on DNA repair. The results showed that the level of excision repair in cells derived from young virgin (YV) rats grown in the presence of HCG (10 units/ml) was 2.5-4.0 times higher than the level exhibited by control YV cells and 1.5-2.5 times over that obtained for cells from old virgin and parous rats. The effect of HCG on DMBA-DNA binding was also determined in YV cells cultured in the presence of HCG (10 units/ml). Results from this study indicated that DMBA-DNA binding was inhibited by 30-40% in HCG-treated cells as compared to control cells. DNA binding of DMBA was also determined with mammary epithelial cells from YV rats which were given subcutaneous injections of HCG (5 units/rat) 5 times per week for 4 weeks. Using this in vivo-in vitro protocol, DMBA-DNA binding was 17-51% lower in cells from HCG-treated rats than in cells derived from control saline-treated rats. These results suggest that the protective effect provided by HCG against DMBA-induced mammary tumorigenesis may be attributed to its ability to inhibit binding of the carcinogen to mammary cell DNA and to its ability to increase the level of excision repair in the cells.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1994

Circulating inhibin levels in lactating and nonlactating women.

OBJECTIVE: To investigate the role of inhibin in the human puerperium, by measuring serum levels of immunoreactive inhibin in both lactating and nonlactating women. DESIGN: Prospective, comparative, open study. SETTING: Department of obstetrics and gynecology of a university hospital. PATIENTS: Fourteen healthy women who delivered at term: seven lactating women and seven nonlactating women treated with the dopamine-agonist CV 205-502. MAIN OUTCOME MEASURES: Serum immunoreactive inhibin, PRL, FSH, LH, E2, and P. RESULTS: All women showed a rapid decline of immunoreactive inhibin levels during the first postpartum days. Thereafter the pattern depended on the way of feeding. Nonlactating women, with their rapid return of pituitary and ovarian function, showed increasing immunoreactive inhibin levels to a maximum on day 24 (950 +/- 180 U/L). Lactating women did not show ovarian activity despite high FSH levels, and immunoreactive inhibin stayed on a low level (230 +/- 40 U/L on day 24). There was a significant correlation between immunoreactive inhibin and E2. CONCLUSIONS: The rapid decline of immunoreactive inhibin (elimination of placental hormone) is followed by an increase in nonlactating women (production by the maturing follicle) and by persistently low levels in lactating women. The lack of adequate levels of immunoreactive inhibin in lactating women may be an explanation of the relatively high FSH levels during lactation.

Aminoquinolines↗
PubMed1989

Triplet pregnancy following oocyte donation to a functionally agonadal woman.

Reported is the first triplet gestation following oocyte donation to an agonadal woman. The transfer of five ova resulted in implantation of all five, with continued embryonic development in three. Pregnancy support was provided by exogenously administered oral E2 and intramuscular P for 100 days, at which time placental hormone production solely maintained the gestations.

Adult↗
PubMedDate not supplied

Cellular localization of rat placental lactogen II and rat prolactin-like proteins A and B by in situ hybridization.

In situ hybridizations using 35S-labelled antisense and sense RNA probes of rPLII, rPLP-A and rPLP-B were carried out on developing rat placenta to determine which cell types synthesized each specific mRNA. Cellular localization of the sites of synthesis of these placental RNAs would help to decide whether these proteins were functioning in the mother of the fetus. The cells of the basal zone are known to have access only to the maternal blood supply, while the labyrinth region is supplied by both maternal and fetal blood vessels. The data in this paper show that at day 12 of pregnancy the rPLII mRNA is synthesized in the primary and secondary giant cells. At later days, hybridization is seen in both the giant cells of the basal zone, and cells in the labyrinth, suggesting that rPLII has a function not only in the mother, but also in the fetus. The rPLP-A mRNA is synthesized in both the giant cells and the cytotrophoblasts of the basal zone. No hybridization is seen to any cells in the labyrinth, even at the later days when it appears that all cytotrophoblasts synthesize rPLP-A mRNA. The rPLP-B mRNA is synthesized exclusively by the cytophoblasts of the fetal placenta. Like rPLP-A, all these cells synthesize this mRNA in the late term placenta. The synthesis of the rPLP-A and rPLP-B mRNAs in cells which have access only to the maternal circulation suggest that they have a role in the mother.

Animals↗
PubMedDate not supplied

Sheep trophoblast in monolayer cell culture.

Methods are described for the preparation and maintenance of ovine trophoblast in monolayer cell culture, and for the preparation of cultured cells for ultrastructural examination. Monolayers grown from dispersed and explanted primary cultures were maintained in consecutive subcultures for periods of 12 to 16 weeks. Towards the end of the first week of incubation high concentrations as the cultured developed. In the second week of incubation small binucleate cells were seen in cultures prepared for electron microscopy. By the 14th day larger binucleate cells were visible at the outer edges of the developing monolayer, and by the third to fourth week 25 to 40 per cent of the cells in culture were in binucleate form. Mature binucleate cells seeded in primary dispersed cultures did not survive beyond the 14th day. The result suggest that (a) the binucleate cells which first appear in monolayers of cultured trophoblast during the second week of incubation are formed by nuclear division of uninucleate cells and not from mature binucleate cells seeded in primary dispersed cultures; and (b) there may be a correlation between the numbers of binucleate cells present in the monolayer and the rate of production of ovine placental lactogen. Monolayer cultures of sheep trophoblast may well provide a useful and relatively inexpensive experimental system for the study of binucleate cells and the mechanisms of placental hormone production.

Animals↗
PubMed1996

The pattern of expression of insulin-like growth factor (IGF). IGF-I receptor and IGF binding protein (IGFBP) mRNAs in the rhesus monkey placenta suggests a paracrine mode of IGF-IGFBP interaction in placental development.

Insulin-like growth factors (IGFs) and their binding proteins (IGFBPs) act as paracrine factors at or close to the sites of biosynthesis, i.e. cellular sites of expression of specific nRNAs. To determine the developmental pattern of expression of IGF-I, IGF-II, IGF-I R and IGFBP 1-6 mRNAs in the rhesus monkey placenta, in situ hybridization histochemistry was performed in placentae and fetal membranes from 65 days until term (165 +/- 5 days). IGF-I mRNA was not detectable in any of the specimens examined. IGF-II mRNA was localized abundantly in the placenta (syncytiotrophoblasts of the chorionic villi and the anchoring villi, and the extravillous cytotrophoblasts), and in the fetal membranes (chorion and amnion). IGF-I R mRNA was expressed predominantly in the decidua. All IGFBP mRNAs (IGFBP-1 to -6) were expressed in the maternal decidua in variable abundance. Only some IGFBP mRNAs, notably IGFBP-3 mRNA, was expressed in the fetal tissues, such as the chorionic mesoderm, some extravillous cytotrophoblasts and in the amnion and chorion. Gestational age did not alter the localization or relative abundance of all of the mRNAs studied. These findings suggest a role for IGF-II in the regulation of nutrient transport or placental hormone synthesis and/or secretion in the syncytiotrophoblasts, and a role for IGF-II and IGFBPs in the cell to cell communication and interaction at the feto-maternal interface.

Amnion↗
PubMed2000

The role of NGF in pregnancy-induced degeneration and regeneration of sympathetic nerves in the guinea pig uterus.

In the guinea pig, pregnancy is associated with a generalised depletion of noradrenaline in uterine sympathetic nerves and, in the areas of the uterus surrounding the foetus, by a complete degeneration of sympathetic nerve fibres. These pregnancy-induced changes have been interpreted as a selective effect of placental hormones on the system of short sympathetic fibres arising from the paracervical ganglia. An alternative explanation is that pregnancy affects the neurotrophic capacity of the uterus. We measured NGF-protein levels in the guinea pig uterine horn, tubal end and cervix at early pregnancy, late pregnancy and early postpartum, using a two-site enzyme-linked immunosorbent assay. For comparative purposes the distribution and relative density of noradrenaline-containing sympathetic nerve fibres were assessed histochemically, and tissue levels of noradrenaline were measured biochemically, using high-performance liquid chromatography with electrochemical detection. In all the uterine regions analysed, NGF-protein levels showed a decline at term pregnancy, but in no case was this change statistically significant. After delivery, NGF-protein levels showed a marked increase in the cervix as well as in both the fertile and empty horns. These results suggest that alterations in NGF-protein do not account for the impairment of uterine sympathetic innervation during pregnancy, but may contribute to their recovery after delivery.

Animals↗
PubMed1987

Fetal monitoring. Biochemical methods.

Biochemical tests of fetal well-being are falling into disfavour. Difficulties arise because we are unable to ascribe specific functions to most test substances, and because they have a large normal range. Nevertheless, a critical survey of the evidence suggests biochemical tests have a part to play in antenatal monitoring, albeit a much reduced one. The main test substances are steroids and proteins produced by the trophoblast. These two classes of substances have a quite different metabolism and compartmental distribution, and the appropriate application of assays is different. A variety of progestogens and oestrogens are used as test substances, the most notable being oestriol. In view of their rapid metabolism, steroid assays serve best in pathological conditions of rapid onset. A dynamic test of the conversion of dehydroepiandrosterone to oestradiol has not fulfilled its initial promise. Among the placental proteins, human placental lactogen is most favoured, although some of the newly discovered proteins may have special applications in certain diseases. The use of biochemical tests in early pregnancy has not been sufficiently explored. The test substances may, in early pregnancy, play a more important role in fetal development and biochemical tests, particularly as a screening test to detect patients at risk of later overt disease, may be valuable.

Chorionic Gonadotropin↗
PubMed1994

Structure of human chorionic gonadotropin at 2.6 A resolution from MAD analysis of the selenomethionyl protein.

BACKGROUND: Human chorionic gonadotropin (hCG) is a placental hormone that stimulates secretion of the pregnancy-sustaining steroid progesterone. It is a member of a family of glycoprotein hormones that are disulfide-rich heterodimers, with a common alpha-chain and distinctive beta-chains specific to their particular G-protein linked receptors. RESULTS: We have produced recombinant hCG in mammalian cells as the selenomethionyl protein, and have determined its structure (after partial deglycosylation) at 2.6 A resolution from multiwavelength anomalous diffraction (MAD) measurements. Despite only limited sequence similarity (10% identity), the alpha- and beta-subunits of hCG have similar tertiary folds. Each subunit has a cystine-knot motif at its core of extended hairpin loops. There is a very extensive subunit interface featuring two inter-chain beta-sheets and a unique, disulfide-tethered 'arm' from the beta-subunit which 'embraces' the alpha-subunit. The carboxy-terminal peptide of the beta-subunit, which is rich in O-linked sugars, is disordered. CONCLUSIONS: Structural and sequence comparisons indicate an evolutionary homology, albeit remote, between the glycoprotein hormone chains and other cystine-knot proteins, notably platelet-derived growth factor. Segments of the alpha- and beta-chains that have been convincingly implicated in receptor binding by hCG are juxtaposed on one side of the molecule. A glycosylation site implicated in signal transduction but not in binding is also close to the presumed binding site suggesting a possible coupling between ligand binding and signaling. This study with selenomethionyl protein produced in mammalian cells extends the realm of MAD phasing.

Amino Acid Sequence↗
PubMed2003

Human placenta as an endocrine organ.

The placenta is a unique, autonomous and transient organ. It ensures maternal-fetal exchanges and is also involved in maternal tolerance of feto-paternal antigens. The human placenta is characterized by the major invasion of the trophoblast, which comes in contact with the maternal blood, and by the intensity and the specificity of its endocrine functions. Placental hormones are required for the establishment and maintenance of pregnancy, adaptation of the maternal organism to pregnancy, fetal growth and well being, and development of the mechanisms involved in parturition. The endocrine tissue of the placenta is the syncytiotrophoblast, which covers the chorionic villi, and arises from the fusion of the cytotrophoblasts. In this review we will summarize the particulars of human syncytiotrophoblast development and endocrine functions.

Endocrine System↗
PubMed2000

Hydatidiform moles and the long-term risk of breast cancer (Sweden).

OBJECTIVES: The etiology of breast cancer is only partially understood. Based on the findings that pregnancies reduce breast cancer risk, a possible inverse association between exposure to the placental hormone human chorionic gonadotropin (hCG) and the risk of breast cancer has been suggested. Hydatidiform mole, a gestational trophoblastic disease, is associated with a high expression of hCG. We performed a population-based cohort study in which women with a history of hydatidiform mole were followed up for future cancer outcomes. METHODS: All 3371 women with a notification of hydatidiform mole in the Swedish Cancer Registry between 1958 and 1993 were followed up for future cancer outcomes by record linkages within the registry. RESULTS: In a total of 57,075 person-years of follow-up, 59 women had a diagnosis of breast cancer during follow-up, yielding an overall standardized incidence ratio of 1.3 (95% CI 1.0-1.7). CONCLUSION: This finding is not consistent with the hypothesis of a protective effect of hCG exposure on breast cancer risk, but rather suggests an adverse association.

Adult↗
PubMed1990

Protective effect of chorionic gonadotropin on DMBA-induced mammary carcinogenesis.

The effect of the placental hormone chorionic gonadotropin (hCG) on 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary tumours was studied in young virgin Sprague-Dawley rats. This hormone when administered at a dose of 100 IU day-1 does not induce toxic effects, measured as alterations in body weight or weight of endocrine organs, and has a reversible effect on oestrous cycle. The lack of toxicity and the fact that hCG treatment terminated prior to administration of the chemical carcinogen DMBA protects the mammary gland from malignant transformation, led us to test the effect of hCG treatment on DMBA-initiated mammary tumours. Fifty day-old virgin Sprague-Dawley rats received intragastrically 8 mg DMBA per 100 g body weight and were divided into two groups: group I animals were treated with DMBA only and group II received DMBA at age 50 and in addition, a daily intraperitoneal injection of 100 IU hCG for days 21-81 post carcinogen administration. Tumorigenic response was evaluated by biweekly palpation of all animals and by complete autopsy 24 weeks after DMBA treatment. Group I animals developed an incidence of 100% of both tumours and adenocarcinomas. Group II animals developed a significantly lower incidence of tumours and adenocarcinomas, 51.5% and 45.5% respectively. In both groups lesions developed more frequently in thoracic than in abdominal mammary glands. It is postulated that hCG treatment, probably through stimulation of ovarian oestrogen and progesterone synthesis, induces differentiation of mammary epithelium that although affected by the carcinogen can still be rescued from malignant transformation.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed2002

BMP4 initiates human embryonic stem cell differentiation to trophoblast.

The excitement and controversy surrounding the potential role of human embryonic stem (ES) cells in transplantation therapy have often overshadowed their potentially more important use as a basic research tool for understanding the development and function of human tissues. Human ES cells can proliferate without a known limit and can form advanced derivatives of all three embryonic germ layers. What is less widely appreciated is that human ES cells can also form the extra-embryonic tissues that differentiate from the embryo before gastrulation. The use of human ES cells to derive early human trophoblast is particularly valuable, because it is difficult to obtain from other sources and is significantly different from mouse trophoblast. Here we show that bone morphogenetic protein 4 (BMP4), a member of the transforming growth factor-beta (TGF-beta) superfamily, induces the differentiation of human ES cells to trophoblast. DNA microarray, RT-PCR, and immunoassay analyses demonstrate that the differentiated cells express a range of trophoblast markers and secrete placental hormones. When plated at low density, the BMP4-treated cells form syncytia that express chorionic gonadotrophin (CG). These results underscore fundamental differences between human and mouse ES cells, which differentiate poorly, if at all, to trophoblast. Human ES cells thus provide a tool for studying the differentiation and function of early human trophoblast and could provide a new understanding of some of the earliest differentiation events of human postimplantation development.

Bone Morphogenetic Protein 4↗
PubMed2005

[A role of PPARgamma in reproduction?].

Synthetic molecules of the glitazone family are currently used in the treatment of type II diabetes. Glitazones also improve secondary pathologies that are frequently associated with insulin resistance such as the polycystic ovary syndrome (PCOS). Glitazones bind to the peroxysome proliferator-activated receptor gamma (PPARgamma), a nuclear receptor which is highly expressed in adipose tissue. PPARgamma also binds natural ligands such as long-chain fatty acids. Recently, several groups have shown that PPARgamma is also highly expressed in ovarian granulosa cells, and that glitazones are able to modulate in vitro granulosa cell proliferation and steroidogenesis in several species. These recent data raise new questions concerning the underlying mechanism of the effect of glitazones on PCOS. One might hypothesize, as for other << glucophage >> molecules such as metformin, that it is the general improvement of glucose metabolism and insulin sensitivity by glitazones which indirectly, and via an unknown mechanism, ameliorates ovarian functionality. The data discussed here suggest now an alternative possibility, that glitazones act directly at the ovarian level. Moreover, PPARgamma also seems to play a key role in the maturation of the placenta. In particular, inactivation of PPARgamma in mice is lethal, since the foetus is unable to develop because of alterations of placental maturation. In women, the activation of PPARgamma in placenta leads to an increase of placental hormone secretion. Overall, these results raise some questions about the role of natural ligands of PPARgamma such as long chain fatty acids on female fertility and the interactions between energy metabolism and reproduction in general.

Animals↗
PubMed2002

Cytokines of the placenta and extra-placental membranes: roles and regulation during human pregnancy and parturition.

Summary In an earlier, companion, review, we concluded that cytokines produced by the placenta and associated membranes are likely to be involved in control of the processes of implantation and placental development (Bowen et al., 2002). In this review, we discuss evidence that cytokines continue to be part of a paracrine/autocrine regulatory network in the placenta and membranes throughout the mid and late stages of gestation. Cytokines are involved in regulation of placental growth during these later stages of pregnancy and also function to protect the fetus from pathological organisms. The evidence, while not entirely consistent, suggests that production of certain cytokines within the extraplacental membranes is altered during normal term parturition, whereas in the villous placenta evidence of labour-associated changes is much more equivocal. Roles for cytokines have been postulated in many facets of parturition, including expulsion of the fetus by uterine contractions, membrane rupture, and dilation of the cervix. Imbalances and disruptions to the cytokine milieu have been implicated in a number of diseases of pregnancy involving abnormalities of both placental growth/establishment and initiation of parturition. Cytokine secretion induced by intrauterine infection is associated with increased occurrence or severity of some neonatal diseases. This wealth of data supports the view that cytokines are an integral part of a functional regulatory/communication network operating within the placental-maternal unit during normal gestation.

Bronchopulmonary Dysplasia↗