scholarly journals Repeated maternal glucocorticoid administration and the developing liver in fetal sheep

2002 ◽  
Vol 175 (2) ◽  
pp. 535-543 ◽  
Author(s):  
DM Sloboda ◽  
JP Newnham ◽  
Keyword(s):  
Hpa Axis ◽  
Plasma Glucose ◽  
Glucocorticoid Receptors ◽  
Fetal Liver ◽  
Mrna Levels ◽  
Fetal Sheep ◽  
Insulin Levels ◽  
Protein Levels ◽  
Cord Plasma ◽  
Glucocorticoid Administration

Prenatal glucocorticoid exposure has been associated with a reduction in birth weight and postnatal alterations in glucose homeostasis and hypothalamic-pituitary-adrenal (HPA) axis function. The mechanisms underlying these responses are unknown, although changes in fetal hepatic development may play an important role. The fetal liver produces key regulators of fuel metabolism and of the developing HPA axis that are altered by glucocorticoids. The local availability of glucocorticoids is regulated, in part, by corticosteroid-binding protein (CBG), glucocorticoid receptors (GR) and by the enzyme 11beta-hydroxysteroid dehydrogenase (11betaHSD), but the effects of maternal glucocorticoid administration on the expression of these genes in the fetal liver are unknown. 11betaHSD1 is the predominant form of this enzyme present in the liver and is responsible for the conversion of cortisone to cortisol. To determine if prenatal glucocorticoid exposure alters fetal hepatic regulation of CBG, 11betaHSD1 and GRs, we treated pregnant ewes with betamethasone (0.5 mg/kg) intramuscularly at 104, 111 and 118 days of gestation (term 150 days). Animals were killed at 125 or 146 days of gestation. Maternal betamethasone administration did not alter mean cord plasma glucose but significantly decreased cord plasma insulin levels (P<0.05) at 125 days of gestation. At 146 days of gestation, cord plasma glucose levels were significantly increased without alterations in insulin levels following maternal betamethasone treatment (P<0.05). Maternal betamethasone administration resulted in a significant increase in fetal hepatic 11betaHSD1 mRNA and protein levels at 125 days of gestation (P<0.05). CBG mRNA levels were significantly elevated over control at 125 days although levels of CBG protein were not significantly different. GR protein levels were not statistically different at either 125 or 146 days of gestation following glucocorticoid administration. These data suggest that prenatal betamethasone exposure in the ovine fetus results in alterations in cord glucose and insulin levels as well as alterations in hepatic 11betaHSD1 mRNA and protein expression. These changes in 11betaHSD1 increase the potential to generate local cortisol from circulating cortisone. We speculate that this could affect expression of glucocorticoid-dependent hepatic enzymes involved with the regulation of glucose production and HPA responsiveness.

scholarly journals TheKampoMedicine Yokukansan Decreases MicroRNA-18 Expression and Recovers Glucocorticoid Receptors Protein Expression in the Hypothalamus of Stressed Mice

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Shoko Shimizu ◽  
Takashi Tanaka ◽  
Takashi Takeda ◽  
Masaya Tohyama ◽  
Shingo Miyata
Keyword(s):  
Hpa Axis ◽  
Stress Responses ◽  
Glucocorticoid Receptors ◽  
Psychological Symptoms ◽  
Plasma Corticosterone ◽  
Mrna Levels ◽  
Stress Exposure ◽  
Protein Levels ◽  
Hpa Axis Activity ◽  
The Brain

It is well known that glucocorticoid receptor (GR) signaling regulates the hypothalamic-pituitary-adrenal (HPA) axis, and GR expression level is associated with HPA axis activity. Recent studies revealed that microRNA- (miR-) 18 and/or 124a are candidate negative regulators of GR in the brain. TheKampomedicine Yokukansan (YKS) can affect psychological symptoms such as depression and anxiety that are associated with stress responses. In this study, we evaluated the effect of YKS on miR-18 and 124a and GR levels in mice exposed to stress. We found that YKS pretreatment normalized elevated plasma corticosterone levels in stress-exposed mice. In addition, GR mRNA levels were downregulated in the brain following stress exposure. While miR-124a expression levels were not altered in the hypothalamus of stress-exposed mice, miR-18 levels decreased in the hypothalamus of YKS-pretreated mice after stress exposure. Finally, GR protein levels in the paraventricular nucleus (PVN) of the hypothalamus after stress exposure recovered in YKS-pretreated mice. Collectively, these data suggest that YKS normalizes GR protein levels by regulating miR-18 expression in the hypothalamus, thus normalizing HPA axis activity following stress exposure.

Gestational changes in fetal renal and hepatic angiotensinogen mRNA and protein

1998 ◽  
Vol 10 (5) ◽  
pp. 399 ◽  
Author(s):  
David Y. Zhang ◽  
Eugenie R. Lumbers ◽  
June J. Wu
Keyword(s):  
Fetal Liver ◽  
Rnase Protection Assay ◽  
Protein Product ◽  
Late Gestation ◽  
Protection Assay ◽  
Rnase Protection ◽  
Fetal Sheep ◽  
Protein Levels ◽  
Adult Kidney ◽  
Liver And Kidney

The aim of the study was to determine the amount of angiotensinogen expression and its protein product in fetal sheep liver and kidney in the last third of gestation. Angiotensinogen mRNA was measured by RNase protection assay and its protein levels were measured by radioimmunoassay. Levels were measured at 80, 95, 111, 125 and 139 days. Angiotensinogen mRNA was present in all fetal liver and kidney samples tested. The ratio of hepatic angiotensinogen mRNA/18 S rRNA increased by 100% (P<0.001) and angiotensinogen levels increased by 33% (P<0.001) in fetal sheep from 80 to 139 d. Over the same period the ratio of renal angiotensinogen mRNA/18 S rRNA increased by 170% (P<0.001) and renal angiotensinogen protein increased by 41% (P<0.001). The levels of angiotensinogen mRNA and its protein in the adult kidney were less than in kidneys of 139 d old fetuses (P<0.01). There was a direct relationship between levels of angiotensinogen mRNA and its protein in the liver (r = 0.53, P<0.01, n = 25) and in the kidney (r = 0.75, P<0.0001, n = 24). These findings demonstrate that there is a significant increase in both hepatic and renal angiotensinogen gene expression in the last third of gestation in the fetal sheep and that this increase is associated with an increase of angiotensinogen levels in both tissues. This increase in angiotensinogen in late gestation could influence the activity of both the intrarenal and circulating renin angiotensin systems.

Ontogenesis of phase I hepatic drug metabolic enzymes in sheep

2012 ◽  
Vol 24 (3) ◽  
pp. 425 ◽  
Author(s):  
Manoja Pretheeban ◽  
Geoff Hammond ◽  
Stelvio Bandiera ◽  
Wayne Riggs ◽  
Dan Rurak
Keyword(s):  
Similar Data ◽  
Mrna Levels ◽  
Nuclear Factor ◽  
Regulatory Factor ◽  
Fetal Sheep ◽  
Hepatic Drug ◽  
Cdna Sequences ◽  
Protein Levels ◽  
Cyp Enzymes ◽  
Rapid Amplification

Cytochrome P450 (CYP) enzymes are important for the metabolism of many drugs. While there is information on their identity and ontogeny in humans and rodents, similar data in sheep are lacking. In the present study, cDNA sequences of several CYP enzymes (CYP2A6, CYP2C19, CYP2D6) were cloned by rapid amplification of cDNA ends. In adult, newborn and fetal sheep the mRNA and protein levels of these CYPs and the regulatory factor, hepatic nuclear factor 4α (HNF4α) were determined in liver samples using real-time PCR and western blotting. The effect of antenatal glucocorticoid on these enzymes was also studied by i.v. infusion of cortisol (0.45 mg h–1; 80 h) to another group of fetuses. The mRNA and protein levels of the CYPs and HNF4α were low or absent in the fetus, followed by increasing levels in the newborn and adult. Fetal cortisol administration significantly increased the mRNA and protein levels of CYP2D6. Moreover, the correlation observed between the CYP and HNF4α mRNA levels suggests a possible regulatory role for this transcription factor. The findings suggest that fetal and newborn lambs have a low ability to metabolise drugs that are substrates of these enzymes, and that this ability increases with advancing postnatal age, similar to the situation in humans.

scholarly journals Amniotic IGF-I supplementation of growth-restricted fetal sheep alters IGF-I and IGF receptor type 1 mRNA and protein levels in placental and fetal tissues

2005 ◽  
Vol 186 (1) ◽  
pp. 145-155 ◽  
Author(s):  
S Shaikh ◽  
F H Bloomfield ◽  
M K Bauer ◽  
H H Phua ◽  
R S Gilmour ◽  
...  
Keyword(s):  
Late Gestation ◽  
Mrna Levels ◽  
Rt Pcr ◽  
Igf Binding Proteins ◽  
Fetal Sheep ◽  
Hepatic Expression ◽  
Protein Levels ◽  
Igf I ◽  
Igf Receptor

We have previously reported that chronic intra-amniotic supplementation of the late gestation growth-restricted (IUGR) ovine fetus with IGF-I (20 μg/day) increased gut growth but reduced liver weight and circulating IGF-I concentrations. Here we report mRNA and protein levels of IGF-I, the type 1 IGF receptor (IGF-1R) and IGF-binding proteins (IGFBP)-1, -2 and -3 in fetal gut, liver, muscle and placenta from fetuses in that earlier study in an attempt to explain these contrasting results. mRNA and protein were extracted from tissues obtained at post mortem at 131 days of gestation (term, 145 days) from three groups of fetuses (control, IUGR+saline and IUGR+IGF-I, n=9 per group). Control fetuses were unembolised and untreated. In the IUGR groups, growth restriction was induced from 113 to 120 days by placental embolisation; from 120 to 130 days fetuses were treated with daily intra-amniotic injections of either saline or 20 μg IGF-I. mRNA was measured by RT-PCR or real-time RT-PCR, and protein by Western blot. In liver, muscle and placenta, IGF-I mRNA and protein levels were reduced by between 8 and 30% in IGF-I-treated fetuses compared with saline-treated fetuses and controls with no change in IGF-1R mRNA or protein levels. In contrast, in the gut, IGF-I mRNA and protein levels were not significantly altered with IGF-I treatment, but IGF-1R levels were increased, especially in the jejunum. Immunolocalisation demonstrated that IGF-1R expression was confined to the luminal aspect of the gut. mRNA levels of all three IGFBPs were reduced in the gut of IGF-I-treated fetuses, but hepatic expression was significantly increased. These data demonstrated tissue-specific regulation of IGF-I, IGF-1R and IGFBPs-1, -2 and -3 in response to intra-amniotic IGF-I supplementation, though the underlying mechanisms remain obscure.

Characterization of an ovine glucocorticoid receptor cDNA and developmental changes in its mRNA levels in the fetal sheep hypothalamus, pituitary gland and adrenal

1992 ◽  
Vol 8 (2) ◽  
pp. 173-180 ◽  
Author(s):  
K. Yang ◽  
G. L. Hammond ◽  
J. R. G. Challis
Keyword(s):  
Pituitary Gland ◽  
Relative Abundance ◽  
Glucocorticoid Receptors ◽  
Mrna Translation ◽  
Developmental Changes ◽  
Mrna Levels ◽  
Fetal Sheep ◽  
Tissue Specific ◽  
Fetal Tissues ◽  
Pituitary Glands

ABSTRACT Fetal sheep tissues possess glucocorticoid receptors (GR), and these change in number during the last two-thirds of gestation. There is, however, no information about developmental changes in tissue GR mRNA levels which might account for alterations in fetal GR content. We have therefore cloned and sequenced a 942 bp GR cDNA from a sheep liver cDNA library, and used it to study the relative abundance of GR mRNA in fetal and neonatal sheep tissues. Analysis of the cDNA revealed a partial sequence of the ovine GR which displayed over 80% identity with residues 143–453 in human GR and 163–472 in rat GR. Furthermore, the first zinc finger motif in these receptors was perfectly conserved among species. The relative abundance of GR mRNA was studied in hypothalami, anterior pituitary glands and adrenals in fetuses at days 60–70, 100–110, 125–130 and at term (approximately 145 days), and in newborn lambs. Total RNA extracts (20 μg) were analysed by Northern blot analysis. A single 5.6kb transcript was detected in all three fetal tissues, and its relative abundance did not change significantly throughout gestation. However, in newborn lambs, levels of GR mRNA increased significantly in the hypothalamus and pituitary gland but decreased to undetectable levels in the adrenal. These tissue-specific changes in the relative abundance of GR mRNA did not correlate with alterations in GR content in fetal tissues, which suggests that the latter may reflect alterations in GR mRNA translation, subsequent modifications and/or GR turnover. In addition, the pattern of developmental changes in GR mRNA content of the adrenal differs from that of the hypothalamus and pituitary gland in neonatal lambs, and indicates that tissue-specific factors may influence GR gene expression in neonatal sheep.

Leukemia inhibitory factor regulates glucocorticoid receptor expression in the hypothalamic-pituitary-adrenal axis

2005 ◽  
Vol 289 (5) ◽  
pp. E857-E863 ◽  
Author(s):  
Anastasia Kariagina ◽  
Svetlana Zonis ◽  
Mahta Afkhami ◽  
Dmitry Romanenko ◽  
Vera Chesnokova
Keyword(s):  
Glucocorticoid Receptor ◽  
Hpa Axis ◽  
Leukemia Inhibitory Factor ◽  
Dominant Negative ◽  
Receptor Expression ◽  
Inhibitory Factor ◽  
Mrna Levels ◽  
Hypothalamic Pituitary Adrenal ◽  
Protein Levels

Leukemia inhibitory factor (LIF) is a pleiotropic cytokine belonging to the gp130 family. LIF is induced peripherally and within the brain during inflammatory or chronic autoimmune diseases and is a potent stimulator of the hypothalamic-pituitary-adrenal (HPA) axis. Here we investigated the role of LIF in mediating glucocorticoid receptor (GR) expression in the HPA axis. LIF treatment (3 μg/mouse, ip) markedly decreased GR mRNA levels in murine hypothalamus (5-fold, P < 0.01) and pituitary (1.7-fold, P < 0.01) and downregulated GR protein levels. LIF decreased GR expression in murine corticotroph cell line AtT20 within 2 h, and this effect was sustained for 8 h after treatment. LIF-induced GR mRNA reduction was abrogated in AtT20 cells overexpressing dominant-negative mutants of STAT3, indicating that intact JAK-STAT signaling is required to mediate LIF effects on GR expression. Conversely, mice with LIF deficiency exhibited increased GR mRNA levels in the hypothalamus and pituitary (3.5- and 3.5-fold, respectively; P < 0.01 for both) and increased GR protein expression when compared with wild-type littermates. The suppressive effects of dexamethasone on GR were more pronounced in LIF-null animals. These data suggest that LIF maintains the HPA axis activation by decreasing GR expression and raise the possibility that LIF might contribute to the development of central glucocorticoid resistance during inflammation.

Ontogeny and effect of cortisol on vasopressin-1b receptor expression in anterior pituitaries of fetal sheep

2003 ◽  
Vol 284 (1) ◽  
pp. R51-R56 ◽  
Author(s):  
Sharla F. Young ◽  
Jennifer L. Smith ◽  
Jorge P. Figueroa ◽  
James C. Rose
Keyword(s):  
Receptor Expression ◽  
Late Gestation ◽  
Mrna Levels ◽  
Fetal Sheep ◽  
Fetal Plasma ◽  
Protein Levels ◽  
Receptor Mrna ◽  
Naturally Occurring ◽  
V1b Receptor

Corticotroph responsiveness to arginine vasopressin (AVP) increases during late gestation in fetal sheep. The mechanism of this increase in AVP responsiveness is currently unknown but could be related to an increase in vasopressin type 1b (V1b) receptor expression in the pituitary during development. To determine if there are ontogenic changes in V1b receptor expression that may help explain the changes in ACTH responses to AVP, we studied pituitaries from three groups of fetal sheep [100, 120, or 140 days gestational age (dGA)]. V1b receptor mRNA and protein significantly decreased by 140 dGA. Peak V1b mRNA levels were detected at 100 dGA, while peak V1b protein levels were detected at 120 dGA. The reduction in V1b receptor expression in late gestation may be due to the naturally occurring peripartum increase in fetal plasma cortisol because cortisol infusion at 122–130 dGA decreased V1b receptor mRNA. Thus there is a marked decrease in the expression of the V1b receptor in the pituitary during fetal development, leaving the role of the V1b receptor in increasing AVP responsiveness uncertain.

scholarly journals Differential Effects of a Perioperative Hyperinsulinemic Normoglycemic Clamp on the Neurohumoral Stress Response during Coronary Artery Surgery

2006 ◽  
Vol 91 (10) ◽  
pp. 4144-4153 ◽  
Author(s):  
H. B. van Wezel ◽  
C. J. Zuurbier ◽  
E. de Jonge ◽  
E. W. C. M. van Dam ◽  
J. van Dijk ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Stress Response ◽  
Clinical Outcome ◽  
Hpa Axis ◽  
Plasma Glucose ◽  
Intervention Group ◽  
Area Under The Curve ◽  
Control Group ◽  
Plasma Acth ◽  
Insulin Levels

Abstract Background: Hyperglycemia in patients undergoing coronary artery bypass grafting (CABG) is associated with adverse outcome. Although insulin infusion strategies are increasingly used to improve outcome, a pathophysiological rationale is currently lacking. The present study was designed to quantify the effects of a perioperative hyperinsulinemic normoglycemic clamp on the neurohumoral stress response during CABG. Methods: Forty-four nondiabetic patients, scheduled for elective CABG, were randomized to either a control group (n = 22) receiving standard care or to a clamp group (n = 22) receiving additionally a perioperative hyperinsulinemic (regular insulin at a fixed rate of 0.1 IU·kg−1·h−1) normoglycemic (plasma glucose between 3.0 and 6.0 mmol·liter−1) clamp during 26 h. We measured the endocrine response of the hypothalamus-pituitary-adrenal (HPA) axis, the sympathoadrenal axis, and glucagon, as well as plasma glucose and insulin at regular intervals from the induction of anesthesia at baseline through the end of the second postoperative day (POD). Results: There were no differences in clinical outcome between the groups. In the control group, hyperglycemia developed at the end of surgery and remained present until the final measurement point on POD2, whereas plasma insulin levels remained unchanged until the morning of POD1. In the intervention group, normoglycemia was well maintained during the clamp, whereas insulin levels ranged between 600 and 800 pmol·liter−1. In both groups, plasma ACTH and cortisol increased from 6 h after discontinuation of cardiopulmonary bypass onward. However, during the clamp period, a marked reduction in the HPA axis response was found in the intervention group, as reflected by a 47% smaller increase in area under the curve in plasma ACTH (P = 0.035) and a 27% smaller increase in plasma cortisol (P = 0.002) compared with the control group. Compared with baseline, epinephrine and norepinephrine increased by the end of the clamp interval until POD2 in both groups. Surprisingly, the area under the curve of epinephrine levels was 47% higher (P = 0.026) after the clamp interval in the intervention group as compared with the control group. Conclusion: A hyperinsulinemic normoglycemic clamp during CABG delays and attenuates the HPA axis response during the first 18 h of the myocardial reperfusion period, whereas after the clamp, plasma epinephrine is higher. The impact of delaying cortisol responses on clinical outcome of CABG remains to be elucidated.

Hypothalamic-pituitary disconnection in fetal sheep blocks the peripartum increases in adrenal responsiveness and adrenal ACTH receptor expression

2005 ◽  
Vol 289 (2) ◽  
pp. R410-R417 ◽  
Author(s):  
Nancy K. Valego ◽  
Yixin Su ◽  
Luke C. Carey ◽  
Sharla F. Young ◽  
Stephen B. Tatter ◽  
...  
Keyword(s):  
Plasma Cortisol ◽  
Receptor Expression ◽  
Late Gestation ◽  
Mrna Levels ◽  
Acth Stimulation ◽  
Fetal Sheep ◽  
Protein Levels ◽  
Overnight Incubation ◽  
Acth Receptor ◽  
Underlying Mechanisms

Although it has been recognized for over a decade that hypothalamic-pituitary disconnection (HPD) in fetal sheep prevents the late gestation rise in plasma cortisol concentrations, the underlying mechanisms remain unclear. We hypothesized that reductions in adrenal responsiveness and ACTH receptor (ACTH-R) expression may be mediating factors. HPD or sham surgery was performed at 120 days of gestation, and catheters were placed for blood sampling. At ∼138 days of gestation, fetuses were killed, and adrenals were removed for cell culture and analyses of ACTH-R mRNA and protein. After 48 h, adrenocortical cells were stimulated with ACTH for 2 h, and the medium was collected for cortisol measurement. The same cells were incubated overnight with medium or medium containing ACTH or forskolin (FSK), followed by ACTH stimulation (as above) and cortisol and cellular ACTH-R mRNA analyses. HPD prevented the late gestation increase in plasma cortisol and bioactive ACTH and reduced adrenal ACTH-R mRNA and protein levels by over 35%. HPD cells secreted significantly less cortisol than sham cells (3.2 ± 1.2 vs. 47.3 ± 11.1 ng·ml−1·2 h−1) after the initial ACTH stimulation. Overnight incubation of HPD cells with ACTH or FSK restored cortisol responses to acute stimulation to levels seen in sham cells initially. ACTH-R mRNA levels in cells isolated from HPD fetuses were decreased by over 60%, whereas overnight incubation with ACTH or FSK increased levels by approximately twofold. Our findings indicate that the absence of the cortisol surge in HPD fetuses is a consequence, at least in part, of decreased ACTH-R expression and adrenal responsiveness.

Alterations in lung expansion affect surfactant protein A, B, and C mRNA levels in fetal sheep

1999 ◽  
Vol 276 (2) ◽  
pp. L239-L245 ◽  
Author(s):  
A. Lines ◽  
L. Nardo ◽  
I. D. Phillips ◽  
F. Possmayer ◽  
S. B. Hooper
Keyword(s):  
Lung Tissue ◽  
Blot Analysis ◽  
Fetal Lung ◽  
Surfactant Protein ◽  
Mrna Levels ◽  
Lung Growth ◽  
Fetal Sheep ◽  
Protein Levels ◽  
Tracheal Obstruction ◽  
Lung Expansion

Obstruction of the fetal trachea is a potent stimulus for fetal lung growth, and it has been suggested that this procedure may be used therapeutically to reverse lung growth deficits in human fetuses with lung hypoplasia. However, little is known about the effects of increased lung expansion on other aspects of lung development. Our aim was to determine the effect of increased and decreased lung expansion on the mRNA levels encoding surfactant protein (SP) A, SP-B, and SP-C in ovine fetal lungs. Lung tissue samples were collected from fetuses exposed to 2, 4, or 10 days of increased lung expansion caused by tracheal obstruction. The mRNA levels for SP-A, SP-B, and SP-C were determined by Northern blot analysis with specific ovine cDNA probes; SP-A protein levels were determined by Western blot analysis. Compared with age-matched (128-day gestational age) control fetuses, SP-A, SP-B, and SP-C mRNA levels in fetal lung tissue were significantly reduced at 2 days of tracheal obstruction and remained reduced at 4 and 10 days. However, SP-A protein levels were not reduced at 2 days of tracheal obstruction, tended to be reduced at 4 days, and were almost undetectable at 10 days. In contrast to tracheal obstruction, 7 days of lung liquid drainage significantly increased SP-C, but not SP-A, mRNA levels in fetal lung tissue compared with age-matched control fetuses. Our results demonstrate that increases in fetal lung expansion, induced by obstruction of the fetal trachea, cause large simultaneous reductions in SP-A, SP-B, and SP-C mRNA levels in the fetal lung as well as a decrease in SP-A protein levels. These data suggest that expression of the genes encoding SPs in the fetal lung are specifically responsive to the degree of lung expansion.

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