Endocrine and paracrine regulation of birth at term and preterm.

We have examined factors concerned with the maintenance of uterine quiescence during pregnancy and the onset of uterine activity at term in an animal model, the sheep, and in primate species. We suggest that in both species the fetus exerts a critical role in the processes leading to birth, and that activation of the fetal hypothalamic-pituitary-adrenal axis is a central mechanism by which the fetal influence on gestation length is exerted. Increased cortisol output from the fetal adrenal gland is a common characteristic across animal species. In primates, there is, in addition, increased output of estrogen precursor from the adrenal in late gestation. The end result, however, in primates and in sheep is similar: an increase in estrogen production from the placenta and intrauterine tissues. We have revised the pathway by which endocrine events associated with parturition in the sheep come about and suggest that fetal cortisol directly affects placental PGHS expression. In human pregnancy we suggest that cortisol increases PGHS expression, activity, and PG output in human fetal membranes in a similar manner. Simultaneously, cortisol contributes to decreases in PG metabolism and to a feed-forward loop involving elevation of CRH production from intrauterine tissues. In human pregnancy, there is no systemic withdrawal of progesterone in late gestation. We have argued that high circulating progesterone concentrations are required to effect regionalization of uterine activity, with predominantly relaxation in the lower uterine segment, allowing contractions in the fundal region to precipitate delivery. This new information, arising from basic and clinical studies, should further the development of new methods of diagnosing the patient at risk of preterm labor, and the use of scientifically based strategies specifically for the management of this condition, which will improve the health of the newborn.

Expression and localisation of breast cancer resistance protein (BCRP) in human fetal membranes and decidua and the influence of labour at term.

Breast cancer resistance protein (BCRP) is a multidrug resistant ABC transport protein (ABCG-2). It extrudes a wide range of substrates, including many chemotherapy drugs, steroids and folate. It is present in many cancers, as well as normal tissues, in particular barrier tissues such as the blood-brain barrier, the intestine, blood vessels and the human placenta. Human fetal membranes (amnion and chorion laeve) provide the barrier between the maternal uterine environment and the fetus. In the present study, we defined the expression and localisation of BCRP mRNA and protein in human fetal membranes (amnion and chorion) and attached decidua obtained before and following labour at term. BCRP protein and mRNA was expressed in all tissues examined and the levels of expression were not altered by labour. BCRP was localised to the amnion epithelial cells, chorion trophoblast cells and decidua stromal cells, as well as the endothelial cells of maternal blood vessels in the decidua, but was absent from mesenchymal cells. In the amnion epithelium, BCRP protein was localised to the apical surface, cytoplasm and membrane between cells. In the chorion trophoblast and decidua stromal cells, BCRP protein was localised to the plasma membrane. However, in the chorion trophoblast, BCRP protein was also highly expressed in the nucleus. The level of BCRP protein in the membranes was comparable to that in the placenta. These high levels raise the possibility that this transporter plays an important role in the physiological function of the tissues.

Breast cancer resistance protein (Bcrp1/Abcg2) in mouse placenta and yolk sac: ontogeny and its regulation by progesterone.

Breast Cancer Resistance Protein (BCRP), a recently-discovered transporter belonging to ABC superfamily, is highly expressed within the labyrinth of the placenta, the primary site of exchange between the maternal and fetal circulation. It has been proposed to function as an efflux pump protecting the fetus from a wide range of xenobiotics. It has also been recently shown that the yolk sac, in addition to the placenta, may be involved in transport of certain substances to and from the fetus. We hypothesised that there are changes in placental Bcrp1 (the mouse orthologue of human BCRP) expression during pregnancy and that these correlate with changes in progesterone production that occur in late gestation. We also hypothesised that Bcrp1 is expressed in the yolk sac, and that levels change with advancing gestation. Either whole concepti, or placenta and yolk sac, were collected from pregnant mice and analysed at embryonic (E) day 9.5, 12.5, 15.5 and 18.5 (term approximately E19.5). Peak expression of Bcrp1 mRNA was detected using in situ hybridisation within the placenta at E9.5 and the yolk sac at E12.5. There was a significant decrease thereafter in both tissues (p<0.001). In contrast, expression of Bcrp1 protein as assessed by immunohistochemistry and Western immunoblots did not change significantly during gestation either in the placenta nor the yolk sac, and no sex difference in Bcrp1 protein expression in either tissue was observed at E12.5. Daily progesterone treatment starting at E14.5 and continuing until E18.5 significantly increased maternal progesterone levels, but did not elicit any changes in the Bcrp1 mRNA or Bcrp1 protein expression either in the placenta or the yolk sac. Significant expression of Bcrp1 protein in fetal tissue was evident at the end of gestation, while expression in the fetal brain endothelium was evident as early as E12.5. We suggest that the placenta and the yolk sac, both of which express Bcrp1, may limit fetal exposure to the potentially adverse effects of xenobiotics including therapeutic drugs which the mother may be exposed to during pregnancy. The significant decrease in Bcrp1 mRNA expression in both the yolk sac and the placenta from mid to late gestation may be counter-balanced by an increase in Bcrp1 expression in fetal organs involved in absorption, excretion and protection.

Expression of the multidrug resistance P-glycoprotein, (ABCB1 glycoprotein) in the human placenta decreases with advancing gestation.

The multidrug resistance p-glycoprotein (P-gp), encoded by the ABCB1 gene, is a plasma membrane protein that actively extrudes a wide variety of substances from cells. Preliminary studies in mice have shown that the ABCB1/P-gp can protect the fetus from a number of toxic substances. ABCB1/P-gp is expressed in the human placenta and is potentially capable of protecting the fetus from a large number of drugs and toxins, including herbicides and pesticides. The protein can also extrude various steroids including certain glucocorticoids and may therefore play an important role in regulating fetal access of glucocorticoids. The aim of the present study was to examine the expression profile and cellular localization of ABCB1/P-gp in human placenta throughout gestation. We hypothesized that there would be gestational age-related changes in the expression of the protein. ABCB1/P-gp mRNA was measured by Real-Time PCR using specific probes in tissues obtained from 6 weeks gestation to term. ABCB1/P-gp mRNA levels in placental tissue obtained at 6-10 weeks (n=5) and 24-35 weeks (n=5) were significantly higher than in tissues obtained at term (38-41 weeks gestation) by elective C-section (n=6) or following labor (n=6). The profile of ABCB1/P-gp protein levels, quantified using Western analysis, demonstrated a similar decrease with advancing gestation. At all gestational ages ABCB1/P-gp was localized by immunohistochemistry to the syncytiotrophoblast. In term tissues, it appeared to be localized to some areas of the villi and not others. Together, these data indicate that with advancing gestation there is a decrease in the level of ABCB1/P-gp in the human placenta indicating that the fetus may be more susceptible to toxic insults in the latter part of gestation. Further, the reduction in ABCB1/P-gp expression may contribute to the increased transfer of maternal cortisol to the fetus that is known to occur in late gestation.

Regulation of Multidrug Resistance P-Glycoprotein in the Developing Blood-Brain Barrier: Interplay between Glucocorticoids and Cytokines.

P-glycoprotein (P-gp) encoded by Abcb1 provides protection to the developing brain from xenobiotics. P-gp in brain endothelial cells (BECs) derived from the developing brain microvasculature is up-regulated by glucocorticoids and inhibited by pro-inflammatory cytokines in vitro. However, little is known about how prenatal maternal glucocorticoid treatment can affect Abcb1/P-gp function and subsequent cytokine regulation in foetal BECs. We hypothesised that glucocorticoid exposure increases Abcb1/P-gp in the foetal brain microvasculature and enhances the sensitivity of Abcb1/P-gp in BECs to the inhibitory effects of cytokines. BECs isolated from dexamethasone- or vehicle-exposed foetal guinea pigs were cultured and treated with interleukin-1ß, interleukin-6 or tumour necrosis factor-α, and Abcb1/P-gp expression and function were assessed. Prenatal dexamethasone exposure significantly increased Abcb1/P-gp expression/activity and cytokine receptor levels in BECs of the foetal brain microvasculature. Foetal dexamethasone exposure in vivo also increased the subsequent responsiveness of BECs to pro-inflammatory cytokines in vitro. In conclusion, maternal treatment with synthetic glucocorticoids appears to prematurely mature P-gp mediated drug resistance at the foetal BBB in vivo and profoundly impact the subsequent responsiveness of P-gp to pro-inflammatory cytokines in the foetal BEC. The significance of these findings to foetal brain protection against xenobiotics and other P-gp substrates in vivo requires further elaboration. However, the results of the present study may have implications for human pregnancy and foetal brain protection, particularly in cases of preterm birth combined with infection.

ATP-binding cassette transporters in reproduction: a new frontier.

BACKGROUND: The transmembrane ATP-binding cassette (ABC) transporters actively efflux an array of clinically relevant compounds across biological barriers, and modulate biodistribution of many physiological and pharmacological factors. To date, over 48 ABC transporters have been identified and shown to be directly and indirectly involved in peri-implantation events and fetal/placental development. They efflux cholesterol, steroid hormones, vitamins, cytokines, chemokines, prostaglandins, diverse xenobiotics and environmental toxins, playing a critical role in regulating drug disposition, immunological responses and lipid trafficking, as well as preventing fetal accumulation of drugs and environmental toxins. METHODS: This review examines ABC transporters as important mediators of placental barrier functions and key reproductive processes. Expression, localization and function of all identified ABC transporters were systematically reviewed using PubMed and Google Scholar websites to identify relevant studies examining ABC transporters in reproductive tissues in physiological and pathophysiological states. Only reports written in English were incorporated with no restriction on year of publication. While a major focus has been placed on the human, extensive evidence from animal studies is utilized to describe current understanding of the regulation and function of ABC transporters relevant to human reproduction. RESULTS: ABC transporters are modulators of steroidogenesis, fertilization, implantation, nutrient transport and immunological responses, and function as 'gatekeepers' at various barrier sites (i.e. blood-testes barrier and placenta) against potentially harmful xenobiotic factors, including drugs and environmental toxins. These roles appear to be species dependent and change as a function of gestation and development. The best-described ABC transporters in reproductive tissues (primarily in the placenta) are the multidrug transporters p-glycoprotein and breast cancer-related protein, the multidrug resistance proteins 1 through 5 and the cholesterol transporters ABCA1 and ABCG1. CONCLUSIONS: The ABC transporters have various roles across multiple reproductive tissues. Knowledge of efflux direction, tissue distribution, substrate specificity and regulation of the ABC transporters in the placenta and other reproductive tissues is rapidly expanding. This will allow better understanding of the disposition of specific substrates within reproductive tissues, and facilitate development of novel treatments for reproductive disorders as well as improved approaches to protecting the developing fetus.

Amnion cell prostaglandin E2 stimulatory activity in chorion laeve-conditioned medium.

In this study we demonstrate the presence of a stimulant(s) to amnion cell prostaglandin (PG) E2 production in chorion-conditioned medium (CCM). The CCM induced a dose-dependent increase in amnion cell PGE2 production. This stimulatory activity was eliminated by heat and protease treatment. Maximal stimulation of amnion PGE2 by CCM did not occur until after 2 h of incubation, and treatment with cycloheximide (1 microgram/ml) effectively eliminated the ability of the amnion cells to respond to CCM. Additionally, CCM and arachidonic acid (2-40 microM) were synergistic in their stimulatory actions on amnion PGE2 production. CCM-treated amnion cells recover more quickly from acetylsalicylic acid pretreatment as compared to control. It is concluded that CCM contains a heat-labile protein which stimulates amnion cell PGE2 production by induction of prostaglandin endoperoxide synthase activity.

Kinetic studies on the formation of estrogens from dehydroepiandrosterone sulfate by human placental microsomes.

Using microsomes isolated from term human placentae kinetic analyses of each of the enzymes involved in estrogen synthesis from dehydroepiandrosterone sulfate have been carried out and the following parameters were found: sulfatase, Michaelis-Menten constant (Km) = 16,000 +/- 5,000 nM, maximum velocity (Vm) = 2.0 +/- 0.5 nmol X min-1 X mg protein-1; 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD), Km = 15 +/- 3 nM, Vm = 1.8 +/- 0.4 nmol X min-1 X mg protein-1; aromatase, Km = 14 +/- 4 nM, Vm = 0.12 +/- 0.02 nmol X min-1 X mg protein-1. From these values one can predict that, theoretically, the rate-limiting enzyme in estrogen synthesis from dehydroepiandrosterone sulfate (DS) should change from the sulfatase at low concentrations of substrate to the aromatase at higher concentrations. In order to test this hypothesis we developed a system which allowed the formation of estrogens from DS, dehydroepiandrosterone, and androstenedione to be measured and the appropriate intermediates to be isolated. The sulfatase was found to be rate limiting at concentrations of DS below 2 microM and the aromatase was found to be rate limiting at higher concentrations. These data may explain why previous perfusion studies of human placentae indicated the sulfatase was the rate-limiting enzyme in estrogen synthesis yet in vitro studies found that it was the aromatase. Steroids previously shown to inhibit the 3 beta-HSD were examined for their ability to inhibit the formation of estrogens from DS. Although 3 beta-HSD activity was markedly inhibited this had little effect on the overall conversion of DS to estrogens, until high concentrations of inhibitors were used. The data also underline the importance of studying enzyme systems rather than single enzymes when studying steroid synthesis.

Role of arginine-vasopressin (AVP) in stress-induced inhibition of testicular steroidogenesis in normal and in AVP-deficient rats.

It has been recently demonstrated that immobilization stress induces in rats a state of testicular desensitization to gonadotropins as well as a post-cAMP blockade of testosterone (T) biosynthesis. Since arginine-vasopressin (AVP) has recently been found to antagonize in rats the in vitro T-releasing effect of human CG, with this work we have verified whether AVP might be involved in stress-induced inhibition of T biosynthesis. In Sprague-Dawley and Long-Evans adult male rats chronically cannulated in the jugular vein, a small but statistically significant rise of plasma AVP levels was observed after 2 h of immobilization stress. The iv infusion of AVP (1 micrograms/kg/h) to chronically cannulated rats induced a fall of plasma T levels. A dose-dependent inhibition of plasma T values was also observed 3 h after ip administration of AVP (1, 5, 25 micrograms/kg) in animals killed by decapitation. An antagonist of AVP pressor activity [1-(beta-mercapto-beta 1 beta-cyclopentamethylenepropionic acid), 2-(O-methyl)tyrosine] AVP, antagonized, when injected ip at a dose of 30 micrograms/kg, the T-inhibitory effects of 3 h of immobilization stress. No consistent changes in plasma LH levels were observed in these experiments. To further evaluate the role of AVP in stress-induced T inhibition, AVP-deficient Brattleboro rats were submitted to 2 or 3 h of immobilization stress concomitantly with rats of the original Long-Evans strain. After 2 h and even more after 3 h of stress, plasma T levels fell in Long-Evans rats together with basal and human CG- or cAMP-stimulated T production by Percoll purified Leydig cells. In Brattleboro rats, 2 h of stress had no effects on plasma T levels nor in vitro basal or stimulated T production, whereas 3 h of immobilization were as effective as in Long-Evans animals. These results suggest, therefore, that at least part of T inhibitory effects of immobilization, those occurring during the first 2 h of stress, are due to an AVP-induced, post-cAMP blockade of T biosynthesis. Since plasma corticosterone, during 2 h of stress, rose to similar, albeit smaller, levels in Brattleboro rats as compared to those in Long-Evans animals, this glucocorticoid does not seem to be involved in the testicular effects of stress.(ABSTRACT TRUNCATED AT 400 WORDS)

Prostaglandin production at the onset of ovine parturition is regulated by both estrogen-independent and estrogen-dependent pathways.

A current hypothesis of ovine parturition proposes that fetal adrenal cortisol induces placental E2 production, which, in turn, triggers intrauterine PG production. However, recent evidence suggests that cortisol may directly increase PG production in trophoblast-derived tissues. To separate cortisol-dependent and estrogen-dependent PG production in sheep intrauterine tissues, we infused singleton, chronically catheterized fetuses beginning on day 125 of gestation (term, 147-150 days) with 1) cortisol (1.35 mg/h; n = 5); 2) cortisol and 4-hydroxyandrostendione, a P450aromatase inhibitor (4-OHA: 1.44 mg/h; n = 5); 3) saline (n = 5); or 4) saline and 4-OHA (n = 5). Fetal and maternal arterial blood samples were collected at 12-h intervals starting 24 h before infusion and continuing during treatment for 80 h or until active labor. Uterine contractility was measured by electromyogram recording of myometrial activity. Plasma E2, progesterone (P4), PGE2, and 13,14-dihydro- 15-keto-PGF2alpha were quantified by RIA. PGHS-II messenger RNA (mRNA) and protein expression were determined by in situ hybridization and Western blot analysis, respectively. Data were analyzed by ANOVA (P < or = 0.05). Labor-type uterine contractions were present after 68 h of cortisol infusion and had increased significantly by 80 h. Labor-type uterine contractions were induced after 68 h of cortisol plus 4-OHA infusion, but the contraction frequency remained less than that in the cortisol-treated animals. Fetal cortisol infusion increased fetal and maternal plasma E2 concentrations and decreased the maternal plasma P4 concentration significantly; concurrent 4-OHA infusion attenuated the increase in fetal and maternal plasma E2, but not the decrease in maternal plasma P4. The fetal plasma PGE2 concentration increased after both cortisol and cortisol plus 4-OHA infusion. The maternal plasma 13,14-dihydro-15-keto-PGF2alpha concentration rose after fetal cortisol infusion, but not after cortisol plus 4-OHA infusion. Placental trophoblast PGHS-II mRNA and protein expression were increased significantly after both cortisol and cortisol plus 4-OHA infusion. Endometrial PGHS-II mRNA and protein expression increased after cortisol infusion, but not after cortisol plus 4-OHA infusion. Plasma steroid and PG concentrations, uterine activity pattern, and intrauterine PGHS-II expression were not altered in either control group. We conclude that these data suggest distinct pathways of intrauterine PG synthesis: a cortisol-dependent/E2-independent mechanism within trophoblast tissue leading to elevations in fetal plasma PGE2, and an E2-dependent mechanism within maternal endometrium that leads to increased maternal plasma PGF2alpha and appears necessary for uterine activity and parturition.

Primary culture of cells from human chorion laeve: steroid metabolism and properties of cells grown in defined media supplemented with 0.1% or 10% fetal calf serum.

The purpose of this study was to develop primary cultures of human chorion laeve cells and examine certain aspects of steroid metabolism during culture. Tissues obtained by elective cesarean section at term (38-40 weeks) were dispersed with collagenase. Cells were isolated on Percoll gradients at the interface between 20% and 40% Percoll and examined in primary culture for up to 1 week. Cultures were carried out in chemically defined media supplemented with 10% or 0.1% fetal calf serum (FCS). The morphological and biochemical properties of the cells were different in the two systems. In 0.1% FCS, cells formed clumps of tissue within 16 h of plating, and there was no cell replication. In contrast, in 10% FCS, the cells formed a carpet of tissue and reached confluence after 5 days in culture, resulting in increased DNA and protein content and thymidine incorporation in the dishes. Three steroidogenic enzymes were studied during culture: alkyl steroid sulfatase, estrogen sulfatase and 3 beta-hydroxysteroid dehydrogenase. The sulfatases had higher activities in 0.1% than in 10% FCS, and their activities decreased markedly during the culture period. In contrast, 3 beta-hydroxysteroid dehydrogenase activity was higher in 10% FCS than in 0.1% FCS. Activity remained constant during the culture period in 0.1% FCS and increased in 10% FCS. In the latter system this increase resulted in the enzyme maintaining a constant specific activity during culture. These studies describe two viable systems of chorion laeve cells in primary culture, which may be valuable for studying long term and/or subtle effects on various metabolic aspects of this tissue.

Expression of prostaglandin I(2) synthase, but not prostaglandin E synthase, changes in myometrium of women at term pregnancy.

Prostaglandins (PGs) act as potent uterotonins at the time of labor. Prostaglandin E synthase (PGES) is responsible for the formation of PGE(2), a uterotonin. PGI(2) is synthesized by the prostaglandin I synthase enzyme (PGIS) and contributes to relaxation in the lower uterine segment. We examined the expression of membrane-bound PGES and PGIS in myometrium from pregnant women during preterm and term labor. Tissues were collected from the lower uterine segment from preterm no labor, preterm labor, term no labor, and term labor patients and used for immunohistochemistry and Western blot analysis using specific antibodies. Immunoreactive (ir-) PGES and PGIS proteins were localized to the cytoplasm of myocytes of the myometrium and vascular smooth muscle cells. Ir-PGES was also detected in vascular endothelial cells. Western blot analyses revealed a predominant protein band of 180 kDa, and a second 16-kDa band for ir-PGES and 56-kDa band for ir-PGIS. There was no significant change in ir-PGES protein (180 or 16 kDa) or mRNA levels with preterm or term labor or gestational age. There was a significant decrease in PGIS mRNA and protein with advancing gestational age. We conclude that the gestational age decrease in the inhibitory PGIS is consistent with lessening of its influence in myometrium at the time of labor. The lack of change in PGES indicates that alterations at other points along the pathway of arachidonic acid metabolism may be of greater importance in affecting local changes in PGE(2).

A comparison of clinical and pathological features of young- and old-onset Parkinson's disease.

We compared 46 patients having onset of Parkinson's disease before age 45 years with 52 having onset after age 70. Young-onset cases more often presented with muscular stiffness (43%) and old-onset with difficulty walking (33%). One-third of young-onset cases had off-period dystonia, mostly affecting the legs, but no dystonia was recorded in old-onset cases. Presentation with rest tremor occurred in 41% of young-onset and 63% of old-onset. There were no differences in the number of affected relatives, endocrine disease, personality characteristics, dementia, or dyskinesia. A pathological study of 12 young-onset and 22 old-onset cases showed 24% greater nigral cell loss in the young, but no differences in the basic Lewy body pathology. Median disease duration in young cases was 5 years longer in the clinical study and 12 years longer in the pathological study. These studies show that the Parkinson's disease process is similar in young- and old-onset cases.

Persistent rheumatic chorea.

A 79-year-old woman had rheumatic chorea that persisted after age 5 years and increased in severity at age 73. The continued chorea and late decompensation could have been due to incomplete functional resolution in the basal ganglia and decreasing reserve of striatal neurons with age. Sydenham's chorea persisting into late life has not been reported previously.

New pathologic observations in juvenile onset parkinsonism with dystonia.

A patient with hereditary juvenile onset parkinsonism with dystonia died at age 39. There were Lewy bodies and regionally selective neuronal damage in the substantia nigra pars compacta. These changes closely resemble those seen in Parkinson's disease, and emphasize the selective vulnerability of the ventral tier of the pars compacta in these degenerations.

A prion disease with a novel 96-base pair insertional mutation in the prion protein gene.

There are coding mutations in the prion protein gene in familial Creutzfeldt-Jakob disease (CJD), Gerstmann-Straussler-Scheinker disease, and other phenotypes that make up the inherited prion diseases. Insertional mutations consisting of two, five, six, seven, eight, and nine additional octapeptide repeat elements are seen in the inherited prion diseases and usually present as atypical dementias with considerable intrafamilial phenotypic variability. A four-octarepeat insertion was reported previously in an individual without neurodegenerative disease who died of hepatic cirrhosis. Here we report a novel four-octarepeat insertional mutation in a case with classical clinical, electroencephalographic and histopathologic features of CJD with the unusual finding of pronounced prion protein immunoreactivity of the molecular layer of the cerebellum.

Treatment with a selective MAO B inhibitor prevents loss of dopamine in the nucleus accumbens of MPTP-treated common marmosets.

Administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) to common marmosets induced motor deficits, associated with a marked decrease in the uptake of [3H]dopamine into synaptosomes in the putamen and a reduction in the content of dopamine in both caudate nucleus and nucleus accumbens. Histological analysis showed a marked loss of dopamine-containing cells in the zona compacta of the substantia nigra and less loss in the ventral tegmental area. Treatment of animals with the selective monoamine oxidase (MAO) B inhibitor, MDL 72145 (0.5 or 2.0 mg/kg) prior to, during and following administration of MPTP partially protected animals from the motor abnormalities induced by administration of MPTP alone. Both doses inhibited the onset of akinesia but only the large dose of MDL 72145 prevented the occurrence of other motor abnormalities. Moreover, while MDL 72145 (2.0 mg/kg) prevented the loss in uptake of [3H]dopamine into synaptosomes of the putamen, this was only partly prevented using the smaller dose. Similarly, while MDL 72145 (2.0 mg/kg) prevented loss of dopamine in the caudate, only partial protection was afforded by the smaller dose. However, in the nucleus accumbens, both doses of MDL 72145 prevented the depletion of dopamine, occurring in this region. Histological examination of the substantia nigra showed little or no cell loss in animals receiving the larger dose of MDL 72145 but a moderate cell loss in animals receiving the smaller dose. No damage was observed in the ventral tegmental area of animals treated with MDL 72145 (2.0 mg/kg) and only mild cell loss in those receiving the smaller dose.(ABSTRACT TRUNCATED AT 250 WORDS)

Localization of prostaglandin H synthase type 2 protein and mRNA in term human fetal membranes and decidua.

Prostaglandin (PG) production by human fetal membranes (amnion and chorion laeve) may be important in the onset and progression of labour, cervical ripening and membrane rupture. Prostaglandin H synthase (PGHS) is a key enzyme in PG formation and has two isoforms, a constitutive form (PGHS-1) and an inducible form (PGHS-2). The present study examined the cellular distribution of the PGHS-2 enzyme and PGHS-2 mRNA in term human fetal membranes and decidua prior to and following labour, using immunohistochemistry and in situ hybridization with an 35S-labelled oligonucleotide probe. The PGHS-2 protein was found to be localized in amnion epithelial cells and chorion laeve trophoblast, but was absent or at low levels in the decidual stroma in most tissues, although cells surrounding some of the blood vessels in the decidual did express PGHS-2. In situ hybridization demonstrated that PGHS-2 mRNA had a similar distribution and was localized to amnion epithelial cells, cells in the amnion-chorion mesenchyme, chorion laeve trophoblast and, occasionally, to cells surrounding blood vessels in the decidua. Of particular note was the high mRNA expression in some cells and low expression in other cells, particularly in the chorion, and the low level of PGHS-2 mRNA in decidua. There was no observable difference in the cellular localization of PGHS-2 protein or PGHS-2 mRNA in tissues obtained prior to and following labour. The studies indicate that, at term, the inducible form of PGHS, PGHS-2, is expressed at a high level in fetal tissues in a number of different cell types rather than in the maternal decidua.

Immunohistochemical localization of the glucocorticoid receptor in human fetal membranes and decidua at term and preterm delivery.

The human fetal membranes and decidua may be important in the onset and/or progression of human labor by providing prostaglandins for this process. Glucocorticoids have been implicated in the regulation of prostaglandin production by these tissues but to date there is no direct evidence for glucocorticoid receptors (GRs) being present in human intrauterine tissues. The purpose of the present study was to determine, using immunohistochemistry, whether the human fetal membranes and decidua contained GRs; to determine the localization of receptors to the cytoplasm or nuclei, and to examine the content and distribution of the GRs in tissues obtained during pregnancy following preterm labor (< 37 weeks) and at term prior to and following term labor. Term tissues were obtained prior to labor by elective Caesarean section (n = 9) or following vaginal delivery (n = 9). Tissues from 14 patients who delivered preterm but with no clinical evidence of infection were also examined. Cryostat sections were thaw-mounted onto microscope slides. The immunoreactive GRs were visualized with an Elite Vectastain ABC Kit using a polyclonal antibody prepared against a synthetic peptide corresponding to amino acids 346-367 of the human GR. At term, nuclear GRs were found in amnion epithelial cells, mesenchyme and the chorion laeve. GRs were present, but were less defined, in the decidua. A similar distribution was found in the preterm tissues. However, nuclear staining in the amnion epithelial cells, mesenchymal cells, chorion and decidua was more pronounced in tissues obtained following preterm labor. This study provides direct evidence for the presence of GRs in human fetal membranes and decidua, and suggests the possible importance of multiple cell types in the action of glucocorticoids in these tissues.