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 361 records · Page 20Linked to original sources
PubMed1973

A comparative study of five laboratory tests for foeto-placental dysfunction in late pregnancy.

Five foeto-placental function tests were studied in parallel in normal and abnormal late pregnancies with a view to establishing which test or tests is most satisfactorily able to identify the mother whose foetus is in danger.A critical examination of the levels in blood serum of two enzymes, placental phosphatase isoenzyme and cystine aminopeptidase, the polypeptide hormone placental lactogen (chorionic somatomammotrophin), and the oestrogen oestriol-17beta is described.A correlation was attempted beween clinical data and the results of the above laboratory analyses and also with the daily urine oestrogen output. The plasma and urine oestriol levels proved generally to be the more useful warning tests in late pregnancy, whilst the plasma cystine aminopeptidase was the least sensitive indicator of foeto-placental dysfunction.

Aminopeptidases↗
PubMed1993

Functional characterization of the alternatively spliced, placental human growth hormone receptor.

The human growth hormone family of peptide hormones is encoded by five genes, pituitary growth hormone (hGH-N), and four placentally expressed genes, growth hormone variant (hGH-V), chorionic somatomammotropin A and B (hCS-A, hCS-B), and prolactin (hPrl). As part of an effort to define the local effects of the placentally expressed members of the GH/Prl family of hormones on the placenta, we have identified an isoform (hGHRd3) of the growth hormone receptor expressed in the placental villi. hGHRd3 mRNA differs from the liver GHR mRNA by the deletion of a 66-base pair segment encoding exon 3. In this study we show that hGHRd3 mRNA encodes a stable and functional receptor. hGHRd3 mRNA is efficiently translated and processed in a rabbit reticulocyte lysate translation system as well as in an in vivo Xenopus laevis oocyte expression system. In Xenopus oocytes hGHRd3 is stably integrated into the cell membrane and binds and internalizes ligand as efficiently as hGHR. hGHRd3 binds all three of the placentally expressed members of the GH/Prl gene family (hGH-V, hCS, and Prl) as well as both the 22 and 20 kDa isoforms of the pituitary hGH-N. The results of the present study strongly support the expression of a functional hGHRd3 isoreceptor in the placenta which may serve in autocrine, paracrine, and/or endocrine activation.

Animals↗
PubMed1985

[Molecular morphology of placental and pituitary hormones: epitope mapping with monoclonal antibodies].

The immunologically and biologically active molecular characteristics of human glycoprotein hormones were studied with the aid of previously produced and characterized monoclonal antibodies (MCA). Placentally derived human chorionic gonadotropin (hCG) and pituitary human follicle stimulating hormone (hFSH) were taken as examples for the use of MCA in the elucidation of molecular morphological and functional correlations and the diagnostic application of these findings. The immunological surface of hCG and of hFSH was probed by 26 MCA to these hormones and bovine luteinizing hormone. In 2-site immunoassays--resembling immunoradiometric assays (IRMA)--pairs of MCA were applied to simultaneous scanning of the molecules. Nine different recognition patterns were distinguished in the case of hCG and 5 for hFSH, reflecting the same number of immunological epitopes. These were either located on the alpha- or beta-subunit or expressed only by the conformationally intact molecule (c-epitopes). The construction of an immunological map revealed an equatorial cluster of alpha-, beta- and c-epitopes, with distinct epitopes on each subunit. This suggests a similar immunological arrangement of epitopes on all human glycoprotein hormones. Antigenic determinants of all 3 main specificities (alpha, beta, c) are involved in the expression of the biological activity of hCG. Surprisingly, hCG is not functionally neutralizable by means of MCA to one of the epitopes (beta 3)--although located on the hormone-specific beta-subunit which is evolutionary highly conserved throughout a large number of mammalian species. On the basis of the epitope map it was possible to establish IRMAs with predictable specificities for selective measurement of hFSH and hCG and its subunit.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Monoclonal↗
PubMed1997

Human placental cholinergic system.

The occurrence of acetylcholine (ACh)-like activity in human placenta, a tissue without innervation, has been known for more than 60 years. However, the non-neuronal functions of ACh in human placenta are not clearly understood. The components of the cholinergic system-ACh, choline acetyltransferase, acetylcholinesterase, butyrylcholinesterase, muscarinic receptors, and nicotinic receptors--in human placenta have been demonstrated by unequivocal methods. Primate placentae store and release ACh by mechanisms similar to those of nervous tissue. However, there are many gaps in our knowledge, which include: (a) endogenous quaternary ammonium compounds other than ACh in human placental extracts; (b) the specificity of placental enzymes; (c) the subtypes and structures of placental muscarinic and nicotinic receptors; and (d) the significance of placental alpha-bungarotoxin binding proteins, ACh receptor stimulation-cellular signaling by second messengers, and activation of immediate early target genes (C-fos, C-jun) encoding transcription factors. Several hypothetical non-neuronal functions of ACh in placenta have been postulated based upon available experimental evidence. These include: (a) regulation of blood flow and fluid volume in placental vessels; (b) opening and closing of trophoblastic channels; (c) induction of contractile properties to myofibroblasts; (d) facilitation of amino acid transport necessary for fetal growth across placenta; (e) release of placental hormones; and (f) modulation of the formation of myometrial and placental prostaglandins in human parturition. All of these roles are reasonable, and some of these roles mav turn out to be linked to one another to influence or maintain placental function.

Acetyl Coenzyme A↗
PubMed2001

The position of the alpha and beta subunits in a single chain variant of human chorionic gonadotropin affects the heterodimeric interaction of the subunits and receptor-binding epitopes.

The glycoprotein hormone family represents a class of heterodimers, which include the placental hormone human chorionic gonadotropin (CG) and the anterior pituitary hormones follitropin, lutropin, and thyrotropin. They are composed of common alpha subunit and a hormone-specific beta subunit. Based on the CG crystal structure, it was suggested that the quaternary subunit interactions are crucial for biological activity. However, recent observations using single chain glycoprotein hormone analogs, where the beta and alpha subunits are linked (NH(2)-CGbeta-alpha; CGbetaalpha orientation), implied that the heterodimeric-like quaternary configuration is not a prerequisite for receptor binding/signal transduction. To study the heterodimeric alignment of the two subunit domains in a single chain and its role in the intracellular behavior and biological action of the hormone, a single chain CG variant was constructed in which the carboxyl terminus of alpha was fused to the CGbeta amino terminus (NH(2)-alpha-CGbeta; alphaCGbeta orientation). The secretion rate of alphaCGbeta from transfected Chinese hamster ovary cells was less than that seen for CGbetaalpha. The alphaCGbeta tether was not recognized by dimer-specific monoclonal antibodies and did not bind to lutropin/CG receptor. To define if one or both subunit domains were modified in alphaCGbeta, it was co-transfected with a monomeric alpha or CGbeta gene. In each case, alphaCGbeta/alpha and alphaCGbeta/CGbeta complexes were formed indicating that CG dimer-specific epitopes were established. The alphaCGbeta/alpha complex bound to receptor indicating that the beta domain in the alphaCGbeta tether was still functional. In contrast, no significant receptor binding of alphaCGbeta/CGbeta was observed indicating a major perturbation in the alpha domain. These results suggest that although dimeric-like determinants are present in both alphaCGbeta/alpha and alphaCGbeta/CGbeta complexes, the receptor binding determinants in the alpha domain of the tether are absent. These results show that generating heterodimeric determinants do not necessarily result in a bioactive molecule. Our data also indicate that the determinants for biological activity are distinct from those associated with intracellular behavior.

Animals↗
PubMed1982

Ethanol-associated selective fetal malnutrition: a contributing factor in the fetal alcohol syndrome.

The pathogenesis of the FAS, particularly the characteristic IUGR, may be due in part to ethanol-related placental injury. Ethanol and/ or acetaldehyde may impair placental transfer of nutrients essential for growth, e.g., amino acids. Such restriction could occur regardless of maternal nutritional status: selective fetal malnutrition. Impairment of placental nutrient transport at critical phases of fetal organogenesis could compound any direct fetotoxic effects of ethanol or acetaldehyde. The effect of ethanol upon human placental hormone synthesis and transport of vitamins, minerals, glucose, and nucleic acid precursors awaits further investigation. Similarly, potential interactions between ethanol and other xenobiotics commonly abused by alcoholics require clarification.

Amino Acids↗
PubMed1981

Secretion of placental lactogen, growth hormone, and prolactin in late pregnant rats.

The secretory patterns of placental lactogen (PL), GH, and PRL were determined in conscious unrestrained late pregnant rats by measurement of the plasma concentrations of each hormone by RIA. Blood samples were collected over a 4-h period at 15-min intervals on days 18 and 19 of gestation. From days 18-19, GH levels increased 2-fold, no change was observed in PRL levels, while PL concentrations increased slightly. There was an ultradian rhythm present in GH and PRL secretion, with a frequency of two to three secretory spikes per 4-h collection period. The variable concentrations of PL in the peripheral circulation were suggestive of an episodic or ultradian secretory pattern. PL levels increased 100% or more within 30 min (i.e. from 485 to 1132 ng/ml) or decreased as much as 65% within 60 min (i.e. from 792 to 247 ng/ml). The relative magnitude of these changes were similar to, but not coincident or correlated with, those for GH.

Animals↗
PubMed1995

In vitro human growth hormone increases human chorionic gonadotropin and progesterone secretion by human placenta at term: evidence of a modulatory role by opioids.

We examined the in vitro effect of human growth hormone (hGH) on hormone placental production and the modulation by opioids of this function. Small placental fragments from 12 term placentas were incubated at 37 degrees C in a 95% air and 5% CO2 atmosphere for 4 h with various concentrations of hGH (1-1000 ng/ml) or naloxone (3-500 ng/ml). Both hGH and naloxone increased the concentrations of human chorionic gonadotropin (hCG) and progesterone in the media. The effect of the hGH was dose-dependent and statistically significant at 10 ng/ml, while naloxone was able to increase hCG and progesterone production only at the highest doses (250-500 ng/ml). The concomitant treatment with ineffective doses of naloxone and hGH was able to enhance hCG and progesterone secretion reaching levels similar to those obtained with the highest doses of hGH alone. High naloxone concentrations significantly decreased both hCG and progesterone secretion induced by high doses of hGH. This study confirms the relevance of growth hormone in sustaining placental endocrine activities and indicates an effect of opioids in modulating these functions.

Chorionic Gonadotropin↗
PubMed1999

Are human placental bed giant cells merely aggregates of small mononuclear trophoblast cells? An ultrastructural and immunocytochemical study.

The ultrastructure of placental bed giant cells in early human pregnancies of 7-12 weeks gestational age is described. Their nature and function was further characterized by confocal immunofluorescence microscopy of paraffin sections labelled for cytokeratin, gap junction connexins (CX) 32 or 43, and placental hormones, alpha-human chorionic gonadotrophin (alpha-HCG) and human placental lactogen (HPL). Placental bed giant cells were observed with two phenotypes; as single large trophoblast cells containing one or more nuclear profiles in a voluminous cytoplasm, and as cell aggregates comprising mononuclear trophoblast cells in close apposition separated by narrow intercellular spaces. Cells within the aggregates are attached to one another by desmosomes, and also possess gap junctions as shown by immunolabelling for CX32 and CX43. By contrast, gap junctions were absent in the true multinucleated giant cells. Organelles present within the cytoplasm of the giant cells and their immunoreactivity for HPL and alpha-HCG suggest protein synthesis.

Cell Aggregation↗
PubMed1996

Ovarian effects upon maternal glucose tolerance.

Ovaries from homozygous diabetic (db/db) female mice were removed and transplanted into the empty left ovarian sacs of normal homozygous (m/m) female mice which had undergone left oophorectomies. To produce controls, the previously removed normal left ovaries were transplanted into the empty left ovarian sacs of other normal (m/m) left oophorectomized females. Glucose tolerance tests were done on the study and control mice before surgery, after surgery, during pregnancy, and after delivery. There were no significant differences in the glucose tolerance test results between study group and controls before or after surgery. However, the study group, when compared to the controls, had a statistically significant glucose intolerance during pregnancy. After delivery, the glucose levels returned to normal. The ovaries from diabetic (db/db) female mice may produce hormones which, by themselves or in concert with the fetal and placental hormones, may produce maternal glucose intolerance during pregnancy.

Animals↗
PubMed1996

High concentrations of immunoreactive inhibin in the plasma of mares and fetal gonads during the second half of pregnancy.

Plasma concentrations of immunoreactive (ir)-inhibin were measured in seven pregnant mares from around Day 140 of gestation to Day 2 after parturition using a heterologous bovine-based radioimmunoassay (RIA). Concentrations of luteinizing hormone (LH), follicle-stimulating hormone (FSH), oestradiol-17 beta, progesterone and relaxin were also measured in the same samples. A marked increase in plasma concentrations of ir-inhibin, FSH and LH occurred between Day 220 and Day 300 of gestation but the concentrations of all three hormones returned to baseline by about Day 320 (three weeks before parturition). In contrast, circulating concentrations of the three placental hormones, oestradiol-17 beta, progesterone and relaxin, increased during the final weeks of pregnancy and then decreased markedly to basal values within two days of parturition. There was a positive correlation between circulating concentrations of ir-inhibin and FSH (r = 0.75, P < 0.01) rather than the expected negative correlation. ir-inhibin was not detected in homogenates obtained at Day 190 of pregnancy and form term placenta, but high concentrations of ir-inhibin were present in homogenates of fetal and newborn gonads. Despite the high concentrations of ir-inhibin in these homogenates, they failed to exert any suppressive bioactivity on FSH secretion by rat pituitary cells cultured in vitro. Furthermore, immunohistochemical staining revealed the presence of inhibin in the interstitial cells of equine fetal gonads at Day 190 of gestation. These findings demonstrate for the first time that high concentrations of ir-inhibin, LH and FSH are secreted into the peripheral circulation of the mare during the second half of pregnancy. However, ir-inhibin present in the plasma of pregnant mares appears to be biologically inactive. This hormone is not presumed to be of placental origin but it is proposed that either the enlarged fetal gonads or the maternal ovaries, or both of these organs, may be a source of inhibin in response to the coincident increase in circulating concentrations of LH and FSH.

Animals↗
PubMedDate not supplied

In vitro secretion of peptide hormones by the human placenta: I. ACTH.

In order to address the question of autonomy of placental hormone secretion, fresh human term placentae were utilized for the preparation of small tissue fragments. The fragment pool was divided over four parallel chambers in a superfusion apparatus and could thus serve as both control and experiment under identical in vitro conditions. Oxygen consumption was substantial and could be maintained for at least 5 h. Adrenocorticotrophic hormone (ACTH) concentrations in the effluent buffer were estimated by radioimmunoassay and bioassay. Both non-specific (membrane depolarization with 45 mM KCl) and specific (isoproterenol at 10(-7) M) stimulation increased the ACTH secretion from 10 to 20 pg/min/g to 60 to 80 pg/min/g. Propranolol blocked the adrenergic stimulation almost completely, indicating the specificity of the effect. Thus, in terms of in vitro ACTH secretion, the human placenta can be stimulated and therefore does not seem to behave in an autonomous manner.

Adrenocorticotropic Hormone↗
PubMed1990

[Placental function in pregnant women with anemia].

The important finding in anemia of pregnancy is impairing hormonal placental function, certain complications of pregnancy and labor. Oxytocinase in the maternal serum was determined to evaluate placental function. Many authors pointed out the important role of the enzyme in biochemical monitoring of human pregnancy. 120 females at the III trimester of gestation were selected at random, but women with additional complications of pregnancy were excluded. Serum iron, total iron binding capacity, hemoglobin level, red blood cells count and hematocrit were assayed. Oxytocinase activity in different periods of gestation was compared to the earlier established normal values. It was found that iron deficit was associated with decreasing activity of the enzyme. It is concluded that there is impaired placental function in pregnancy anemia.

Anemia↗
PubMed1992

Elevated maternal plasma corticotropin-releasing hormone levels in pregnancies complicated by preterm labor.

OBJECTIVES: We investigated whether maternal plasma levels of the placental hormone corticotropin-releasing hormone are elevated in pregnancies complicated by preterm labor. STUDY DESIGN: Mean maternal corticotropin-releasing hormone levels were studied in women who met specific criteria for preterm labor and in women with normal pregnancies. Levels were also compared in the latent and active phases during term labor. RESULTS: In pregnancies complicated by preterm labor, maternal corticotropin-releasing hormone levels were higher than in normal pregnancies; this elevation occurred before labor was diagnosed clinically (p less than 0.05). When preterm labor was associated with infection, the mean levels were not elevated. Mean plasma levels were similar in latent and active phases during labor at term. CONCLUSION: Maternal plasma corticotropin-releasing hormone levels are elevated in association with preterm labor. This elevation does not appear to be due to labor itself and may reflect an early activation of the placenta before the onset of preterm labor.

Corticotropin-Releasing Hormone↗
PubMed1990

Differential expression of human placental growth-hormone variant and chorionic somatomammotropin in culture.

Regulation of human placental growth-hormone variant (hGH-V) in the presence of its own promoter has been studied. At term, 10-20% of placental mRNA is specific for chorionic somatomammotropin (hCS-A and -B) compared with 0.05% hGH-V, yet these genes show more than 90% sequence similarity at the nucleotide level. By using stable gene transfer of intact hGH-V and hCS-A genes into rat pituitary (GC) cells, synthesis and release of hGH-V and hCS are detected. This suggests that hGH-V as well as hCS is secreted during pregnancy. The hCS-A mRNA level is higher than that observed from the hGH-V gene in stably transfected GC cells. Also, a hybrid gene containing hGH-V 5'-flanking DNA was less active than a hybrid hCS-A gene containing equivalent sequences after transient transfection of these cells. This correlates with the binding of a known transcription factor to a proximal region (-97/-66) of the hCS-A promoter, and not the equivalent hGH-V gene sequences. These results indicate that differential expression of hGH-V and hCS in GC cells is related, in part, to the strength of their respective promoters, and suggest a similar mechanism may exist in the placenta.

Animals↗
PubMed1981

[The influence of transcutaneous nerve stimulation (TNS) on hormonal parameters of placental function in cases of placental insufficiency (author's transl)].

The influence of transcutaneous nerve stimulation (TNS) on the hormonal parameters of placental function (HPL and Estriol) in the serum of 39 patients between the 28th and 39th week of pregnancy was investigated. In this patients placental insufficiency was suspected because of low hormonal parameters or a diminished radioisotope placental perfusion test. During a hospitalization of 2 weeks these patients underwent a daily TNS-therapy for 2-3 hours. 2 or 3 hormonal values before these two-weeks therapy and 2 or 3 values after the therapy were compared. A significant difference (p less than 0.05; t-test) was found. HPL and Estriol mean values raised absolutely, but also in comparison to a group of patients of our clinic without placental insufficiency. A correlation between the onset of therapy at a certain week of gestation and it's effect could not be proved. The use of this riskless method as a therapy of placental insufficiency is recommended.

Electric Stimulation↗