Increased maternal cortisol in late-gestation ewes decreases fetal cardiac expression of 11β-HSD2 mRNA and the ratio of AT1 to AT2 receptor mRNA

2006 ◽  
Vol 291 (6) ◽  
pp. R1708-R1716 ◽  
Author(s):  
Seth A. Reini ◽  
Charles E. Wood ◽  
Ellen Jensen ◽  
Maureen Keller-Wood
Keyword(s):  
Blood Vessels ◽  
Renin Angiotensin System ◽  
Left Ventricular ◽  
Receptor Expression ◽  
Late Gestation ◽  
Angiotensin Receptors ◽  
Fetal Sheep ◽  
Igf Receptors ◽  
Adult Kidney ◽  
Cortisol Levels

Moderately elevated maternal cortisol levels late in gestation cause enlargement of the fetal sheep heart. We have used quantitative real-time PCR to examine expression of candidate genes in fetal hearts from mothers in whom cortisol levels were increased (by infusion of 1 mg cortisol·kg−1·day−1) or decreased (by adrenalectomy and replacement to 0.5 mg cortisol·kg−1·day−1) from 115 to 130 days gestation. Control ewes were not treated with steroid. Expression of mineralocorticoid receptor (MR), glucocorticoid receptor (GR), 11β-hydroxysteroid dehydrogenases 1 and 2 (11β-HSD1 and -2), IGF I and II, IGF receptors 1 and 2 (IGF-1R and IGF-2R), endothelial nitric oxide synthase, VEGF, myotrophin, angiotensinogen, the angiotensin receptors 1 and 2 (AT1R and AT2R), and the angiotensin converting enzymes 1 and 2 were measured. MR mRNA abundance in fetal hearts was found to be similar to that in adult kidney and hippocampus. Although there were no significant changes in most genes, 11β-HSD2 and IGF-1R expression were significantly decreased in the high cortisol group and 11β-HSD2 expression negatively correlated to left ventricular wall thickness. There was also a significant change in the ratio of AT receptor expression, with increased AT2R and decreased AT1R in the high cortisol group. MR, GR, and 11β-HSD1 immunoreactivity was found in cardiomyocytes and cardiac blood vessels in 126–128 day fetal sheep; in contrast 11β-HSD2 staining was predominantly in blood vessels. These results indicate that cortisol could indeed act in the fetal heart to induce enlargement and suggest that the renin-angiotensin system may play a role.

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.

Cardiac modulations of ANG II receptor expression in rats with hypoxic pulmonary hypertension

2002 ◽  
Vol 283 (2) ◽  
pp. H733-H740 ◽  
Author(s):  
Christophe Adamy ◽  
Patricia Oliviero ◽  
Saadia Eddahibi ◽  
Lydie Rappaport ◽  
Jane-Lise Samuel ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Right Ventricular ◽  
Chronic Hypoxia ◽  
Renin Angiotensin System ◽  
Left Ventricular ◽  
Receptor Expression ◽  
Mrna Levels ◽  
Hypoxic Pulmonary Hypertension ◽  
Cardiac Ventricles ◽  
The Right

Right ventricular myocardial hypertrophy during hypoxic pulmonary hypertension is associated with local renin-angiotensin system activation. The expression of angiotensin II type 1 (AT1) and type 2 (AT2) receptors in this setting has never been investigated. We have therefore examined the chronic hypoxia pattern of AT1 and AT2expression in the right and left cardiac ventricles, using in situ binding and RT-PCR assays. Hypoxia produced right, but not left, ventricular hypertrophy after 7, 14, and 21 days, respectively. Hypoxia for 2 days was associated in each ventricle with a simultaneous and transient increase ( P < 0.05) in AT1 binding and AT1 mRNA levels in the absence of any significant change in AT2 expression level. Only after 14 days of hypoxia, AT2 binding increased ( P < 0.05) in the two ventricles, concomitantly with a right ventricular decrease ( P < 0.05) in AT2 mRNA. Along these data, AT1 and AT2 binding remained unchanged in both the left and hypertrophied right ventricles from rats treated with monocrotaline for 30 days. These results indicate that chronic hypoxia induces modulations of AT1 and AT2 receptors in both cardiac ventricles probably through direct and indirect mechanisms, respectively, which modulations may participate in myogenic (at the level of smooth or striated myocytes) rather than in the growth response of the heart to hypoxia.

scholarly journals Synthesis and Secretion of Angiotensin II by the Prostate Gland in Vitro

Endocrinology ◽  
2005 ◽  
Vol 146 (1) ◽  
pp. 392-398 ◽  
Author(s):  
Orla A. O’Mahony ◽  
Stewart Barker ◽  
John R. Puddefoot ◽  
Gavin P. Vinson
Keyword(s):  
Angiotensin Ii ◽  
Seminal Plasma ◽  
Renin Angiotensin System ◽  
At1 Receptor ◽  
Receptor Expression ◽  
Angiotensin Receptors ◽  
Lncap Cells ◽  
Angiotensin System ◽  
Renin Angiotensin ◽  
Rat Prostate

The renin angiotensin system has been shown to have tissue-related functions that are distinct from its systemic roles. We showed that angiotensin II type 1 (AT1) receptors are present in mammalian sperm, and angiotensin II stimulates sperm motility and capacitation. In addition, angiotensin II is present in human seminal plasma at concentrations higher than found in blood. In testing the possibility that the prostate may be the source of seminal plasma angiotensin II, mRNA coding for angiotensinogen, (pro)renin, and angiotensin-converting enzyme were identified by RT-PCR in rat and human prostate and in prostate LNCaP cells, as well as the angiotensin receptors types 1 and 2 (AT1 and AT2) in human tissues and AT1 in rat. In human tissue, immunocytochemistry showed cellular colocalization of renin with the AT1 receptor in secretory epithelial cells. Confirmation of the capacity of the prostate to secrete angiotensin II was shown by the detection of immunoreactive angiotensin in media removed from rat prostate organ cultures and LNCaP cells. Rat prostate angiotensin secretion was enhanced by dihydrotestosterone, but LNCaP angiotensin was stimulated by estradiol. This stimulation was blocked by tamoxifen. Rat prostate AT1 receptor expression was much greater in prepuberal than in postpuberal rats but was not affected by a low-sodium diet. It was, however, significantly enhanced by captopril pretreatment. These findings all suggest the independence of prostate and systemic renin angiotensin system regulation. The data presented here suggest that the prostate may be a source of the secreted angiotensin II found in seminal plasma.

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.

Thyroid hormone modulates renin and ANG II receptor expression in fetal sheep

2005 ◽  
Vol 289 (4) ◽  
pp. R1006-R1014 ◽  
Author(s):  
Kai Chen ◽  
Luke C. Carey ◽  
Nancy K. Valego ◽  
Jingfang Liu ◽  
James C. Rose
Keyword(s):  
Thyroid Hormone ◽  
Receptor Expression ◽  
Late Gestation ◽  
Receptor Subtype ◽  
Ang Ii ◽  
Angiotensin Ii Receptor ◽  
Fetal Sheep ◽  
Fetal Plasma ◽  
Active Renin ◽  
Arterial Blood

Fetal renin-angiotensin system (RAS) activity is developmentally regulated, increasing in late gestation toward term. At the same time, fetal hemodynamic parameters change, with blood pressure increasing and heart rate decreasing. During this period, fetal plasma thyroid hormone concentrations also increase significantly. In this study we utilized the technique of thyroidectomy (TX), which removes thyroid hormone from the circulation, to investigate the importance of thyroid hormone on the developmental changes in the RAS (in plasma, kidney, heart, and lung) and hemodynamic regulation in fetal sheep. TX was performed at 120 days of gestational age (dGA), and control fetuses were sham operated. Immediately before necropsy (∼137 dGA), fetuses were infused with isoproterenol and the hemodynamic responses were noted. TX significantly decreased plasma thyroid hormone concentrations and renal renin mRNA and renal active renin levels but did not change fetal plasma active renin levels. TX decreased both angiotensin II receptor subtype 1 (AT1) mRNA and protein levels in kidney and lung but not in the left ventricle. TX also was associated with increased ANG II receptor subtype 2 (AT2) mRNA and protein at the 44-kDa band in kidney, whereas AT2 protein was decreased at the 78-kDa level in kidney and lung tissue only. TX fetuses had significantly lower basal mean arterial blood pressures (MAP) and heart rates than controls. Isoproterenol infusion decreased MAP in TX fetuses. These findings support the hypothesis that thyroid hormone is important in modulating maturation of RAS and cardiovascular function in the late-gestation fetal sheep.

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.

Effects of intrafetal IGF-I on growth of cardiac myocytes in late-gestation fetal sheep

2009 ◽  
Vol 296 (3) ◽  
pp. E513-E519 ◽  
Author(s):  
Eugenie R. Lumbers ◽  
Min young Kim ◽  
Judith H. Burrell ◽  
Vasumathy Kumarasamy ◽  
Amanda C. Boyce ◽  
...  
Keyword(s):  
Cardiac Hypertrophy ◽  
Cardiac Myocytes ◽  
Ventricular Myocytes ◽  
Contractile Function ◽  
Left Ventricular ◽  
Late Gestation ◽  
Cycle Phase ◽  
Cell Hyperplasia ◽  
Fetal Sheep ◽  
Igf I

Intrafetal insulin-like growth factor (IGF)-I promotes cardiac hypertrophy in the late-gestation fetal sheep; whether these effects are sustained is unknown. IGF-I was infused for 4 days at 80 μg/h from 121 to 125 days of gestation, and its effects at 128 days, 3 days after the infusion stopped, were determined by comparison with untreated fetal sheep. After IGF-I treatment, fetal weights were similar to those in control fetuses but kidney weights were bigger ( P < 0.05), as were spleen weights of male fetuses ( P < 0.05). Cardiac myocytes were larger in female than male fetal sheep ( P < 0.001). IGF-I increased male ( P < 0.001) but not female myocyte volumes. IGF-I did not alter the proportions of uni- or binucleated right or left ventricular myocytes. Female fetal sheep had a greater proportion of binucleated cardiac myocytes than males ( P < 0.05). IGF-I-treated fetuses had a slightly greater proportion of right ventricular nuclei in cell cycle phase G2/M and a reduced proportion of G0/G1 phase nuclei ( P < 0.1). Therefore, evidence for IGF-I-stimulated cardiac cell hyperplasia in fetal sheep in late gestation was limited. In conclusion, the greater sizes and larger proportion of binucleated cardiac myocytes in female fetal sheep suggest that myocyte maturation may occur earlier in females than in males. This may explain in part the male sex-specific responsiveness of cardiac hypertrophy to IGF-I in late gestation. If IGF-I-stimulated cardiomyocyte growth is accompanied by maturation of contractile function, IGF-I may be a potential therapeutic agent for maintaining cardiac output in preterm males.

scholarly journals Periconceptional nutrition programs development of the cardiovascular system in the fetal sheep

2002 ◽  
Vol 283 (3) ◽  
pp. R669-R679 ◽  
Author(s):  
L. J. Edwards ◽  
I. C. McMillen
Keyword(s):  
Cardiovascular System ◽  
Enzyme Inhibitor ◽  
Renin Angiotensin System ◽  
Late Gestation ◽  
Rate Pressure Product ◽  
Fetal Sheep ◽  
Fetal Plasma ◽  
Maternal Undernutrition ◽  
Arterial Blood ◽  
The Impact

It has been proposed that fetal adaptations to intrauterine nutrient deprivation permanently reprogram the cardiovascular system. We investigated the impact of restricted periconceptional nutrition and/or restricted gestational nutrition on fetal arterial blood pressure (BP), heart rate, rate pressure product, and the fetal BP responses to ANG II and the angiotensin-converting enzyme inhibitor captopril during late gestation. Restricted periconceptional nutrition resulted in an increase in fetal mean arterial BP between 115 and 125 days gestation (restricted 41.5 ± 2.8 mmHg, n = 12; control 38.5 ± 1.5 mmHg, n = 13) and between 135 and 147 days gestation (restricted 50.5 ± 2.2 mmHg, n = 8; control 42.5 ± 1.9 mmHg, n = 10) as well as an increase in the rate pressure product in twin, but not singleton, fetuses between 115 and 147 days gestation. Mean BP and fetal plasma ACTH were also positively correlated in twin, but not singleton, fetuses. This is the first demonstration that maternal undernutrition during the periconceptional period results in an increase in fetal arterial BP. This increase occurs concomitantly with an increase in fetal ACTH but is not dependent on activation of the fetal renin-angiotensin system.

scholarly journals Regulation of 11 beta-hydroxysteroid dehydrogenase type 2 activity in ovine placenta by fetal cortisol

2002 ◽  
Vol 172 (3) ◽  
pp. 527-534 ◽  
Author(s):  
KA Clarke ◽  
JW Ward ◽  
AJ Forhead ◽  
DA Giussani ◽  
AL Fowden
Keyword(s):  
Plasma Cortisol ◽  
Inverse Correlation ◽  
Hydroxysteroid Dehydrogenase ◽  
Plasma Cortisol Level ◽  
Late Gestation ◽  
Fetal Sheep ◽  
Fetal Plasma ◽  
Ovine Placenta ◽  
Cortisol Levels

The effect of fetal cortisol on the activity of the type 2 isoform of the enzyme, 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD2), was examined in ovine placenta and fetal kidney by measuring tissue 11 beta-HSD2 activity during late gestation when endogenous fetal cortisol levels rise and after exogenous cortisol administration to immature fetuses before the prepartum cortisol surge. Placental 11 beta-HSD2 activity decreased between 128-132 days and term (approximately 145 days of gestation) in association with the normal prepartum increase in fetal plasma cortisol. Raising fetal cortisol levels to prepartum values in the immature fetus at 128--132 days of gestation reduced placental 11 beta-HSD2 activity to term values. In contrast, 11 beta-HSD2 activity in the fetal renal cortex was unaffected by gestational age or cortisol infusion. When all the data were combined, there was an inverse correlation between the log fetal plasma cortisol level at delivery and placental 11 beta-HSD2 activity, expressed both on a weight-specific basis and per mg placental protein. Fetal cortisol therefore appears to be a physiological regulator of placental, but not renal, 11 beta-HSD2 activity in fetal sheep during late gestation. These findings have important implications, not only for glucocorticoid exposure in utero, but also for the local actions of cortisol within the placental tissues that are involved in initiating parturition in the sheep.

The effect of hypothalamo-pituitary disconnection on the renin-angiotensin system in the late-gestation fetal sheep

2005 ◽  
Vol 288 (5) ◽  
pp. R1279-R1287 ◽  
Author(s):  
Kai Chen ◽  
Luke C. Carey ◽  
Jingfang Liu ◽  
Nancy K. Valego ◽  
Stephen B. Tatter ◽  
...  
Keyword(s):  
Renin Angiotensin System ◽  
Plasma Renin ◽  
Fetal Tissue ◽  
Late Gestation ◽  
Receptor Subtype ◽  
Postnatal Life ◽  
Ang Ii ◽  
Fetal Sheep ◽  
Angiotensin System ◽  
Renin Angiotensin

The activity of the renin-angiotensin system (RAS) increases significantly in the late-gestation fetal sheep. Fetal cortisol is also increased during this time, and it is thought that the increase in cortisol may modulate the RAS changes. Previous studies have examined the effects of cortisol infusion on RAS activity, but the effects of blocking the peripartum increase in cortisol concentrations on the developmental changes in the RAS are not known. Therefore, we utilized the technique of hypothalamic-pituitary disconnection (HPD), which prevents the cortisol surge from occurring, to investigate the importance of the late-gestation increase in cortisol on the ontogenic changes in RAS activity. HPD of fetal sheep was performed at 120 days of gestational age (dGA), and fetuses were delivered between 135 and 139 dGA. Control fetuses were sham operated. HPD blocked the late-gestation cortisol increase but did not alter renal renin mRNA, renal renin or prorenin protein content, nor plasma renin levels compared with sham operated. However, HPD fetuses had increased ANG II receptor subtype 1 (AT1) mRNA and protein expression in the kidney and lungs. ANG II receptor subtype 2 (AT2) expression was not altered in these tissues at either mRNA or protein level. HPD did not change AT1 or AT2 mRNA in the left ventricle but did result in decreased protein levels for both receptors. These studies demonstrate that blockade of the naturally occurring increase in fetal cortisol concentration in late gestation is associated with tissue-specific alterations in expression of AT1 and AT2 receptors. These changes may impact on fetal tissue maturation and hence have consequences in postnatal life.

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