The Effects of Cortisol on the Binucleate Cell Population in the Ovine Placenta During Late Gestation

Abstract Melatonin plays a role as a vasodilator. Vasoactive and angiogenic factors are expressed by placental binucleate cells (BNC) and produce chorionic somatomammotropin (CSH), known to impact fetal and placental growth. We hypothesized that melatonin supplementation and restricted nutrition from mid- to late-gestation would alter CSH concentration and some characteristics of BNC in placenta. At day 50 of gestation, ewes carrying singletons were randomly assigned to a 2 × 2 factorial design and were fed either an adequate (ADQ; 100% NRC; n = 15) or restricted (RES; 60% NRC; n = 15) diet supplemented with 0 (CON, n = 14) or 5 mg of melatonin (MEL; n = 16). Placentomes were collected on day 130 of gestation and preserved in formalin for histological analysis. Cotyledon (COT) were snap frozen for western immunoblotting analyses. Tissue sections were stained using biotinylated Dolichos Biflurus (DBA; a marker of fetal membrane) lectin and fluorescein labeled Texas red-avidin and fluorescein labeled Griffonia Simplifolica (BS) lectin (a marker of BNC). The number, area, and diameter of BNC in COT were determined by image analysis. For immunoblotting, protein was extracted from COT in SDS phosphate buffer, loaded equally, and separated on 12.5% polyacrylamide gels. Protein was transferred to PVDF membranes and incubated with rabbit anti-CSH. Bands were visualized and imaged. Data were analyzed using Proc Mixed procedure of SAS. Melatonin supplementation and restricted nutrition did not affect BNC number, area, or diameter, or CSH protein expression. While we reject our hypothesis that melatonin supplementation and nutrient restriction would alter the CSH concentration and BNC characteristics in COT, we continue to evaluate if the BNC produce angiogenic or vasoactive factors that may influence placental and mammary gland functions in sheep.

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Does the ovine placenta secrete ACTH under normoxic or hypoxic conditions?

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1991.260.2.r389 ◽

1991 ◽

Vol 260 (2) ◽

pp. R389-R395 ◽

Cited By ~ 2

Author(s):

M. Keller-Wood ◽

C. E. Wood

Keyword(s):

Plasma Cortisol ◽

Adrenocorticotropic Hormone ◽

Late Pregnancy ◽

Maternal Plasma ◽

Late Gestation ◽

Fetal Circulation ◽

Fetal Plasma ◽

Hypoxic Conditions ◽

Ovine Placenta ◽

Arterial Po2

In the sheep, maternal plasma cortisol is increased in late pregnancy, and fetal plasma cortisol and adrenocorticotropic hormone (ACTH) rise precipitously in late gestation. In many species, the placenta contains ACTH. These experiments were designed to test whether the ovine placenta contains ACTH and whether there is net secretion of ACTH by the uteroplacental unit into either the maternal or fetal circulation. Pregnant ewes and their fetuses were prepared with maternal and fetal arterial and uterine and umbilical venous catheters. Arterial and venous samples were taken from both sides of the placenta before and during hypoxia induced by the ewe breathing 9-11% O2, and arteriovenous (a-v) differences in ACTH, PO2, PCO2, and progesterone were analyzed. A positive a-v difference in PO2 (48.2 +/- 3.4 mmHg) and negative a-v differences in PCO2 and progesterone (-3.5 +/- 0.7 mmHg and -25 +/- 5 ng/ml, respectively) were found across the placenta in the ewe, and a positive a-v difference in PCO2 (4.8 +/- 0.9 mmHg) and negative a-v differences in PO2 and progesterone (-8.1 +/- 1.5 mmHg and -13 +/- 3 ng/ml, respectively) were found across the placenta in the fetus, indicating that the umbilical and uterine venous catheters were properly placed. Hypoxia decreased fetal and maternal arterial PO2 from 22.8 +/- 1.3 to 13.8 +/- 0.7 and from 98.8 +/- 3.3 to 37.0 +/- 2.6 mmHg, respectively, and increased fetal and maternal arterial ACTH immunoreactivity from 95 +/- 60 to 2,676 +/- 795 and from 149 +/- 21 to 275 +/- 88 pg/ml, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

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

Journal of Endocrinology ◽

10.1677/joe.0.1720527 ◽

2002 ◽

Vol 172 (3) ◽

pp. 527-534 ◽

Cited By ~ 43

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.

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PSI-25 Effects of restricted maternal nutrition and realimentation during gestation on the fetal progenitor cell population in semitendinosus muscle of sheep

Journal of Animal Science ◽

10.1093/jas/skz258.504 ◽

2019 ◽

Vol 97 (Supplement_3) ◽

pp. 248-248

Author(s):

Michaela Mitchell ◽

Amanda E Liefeld ◽

Kristen E Govoni ◽

Kimberly A Vonnahme ◽

Anna T Grazul-Bilska ◽

...

Keyword(s):

Cell Population ◽

Progenitor Cell ◽

Muscle Development ◽

Maternal Nutrition ◽

Control Diet ◽

National Research Council ◽

Dietary Treatment ◽

Late Gestation ◽

Progenitor Cell Population ◽

Myogenic Progenitor

Abstract Satellite cells are muscle stem cells that contribute to postnatal growth. The satellite cell population is established during fetal muscle development, through the retention of Pax7-expressing myogenic progenitor cells. We hypothesized that realimentation during late gestation would ameliorate the negative effect of poor maternal nutrition during mid-gestation on the fetal myogenic progenitor cell population. To test this hypothesis, 47 ewes pregnant with singletons were fed a control diet of 100% of National Research Council (NRC) requirements (CON) starting at day 25 of gestation. At day 50 of gestation, six ewes were euthanized and the remainder were randomly assigned to one of two diets: CON or 60% of CON (RES). On day 90 of gestation, a subset of ewes were euthanized (n = 7 per treatment) and fetal semitendinosus samples were collected. The remaining ewes were maintained on the current diet (CON-CON, RES-RES) or switched to the alternative diet (CON-RES, RES-CON). On day 130 of gestation, all ewes were euthanized for fetal sample collection (n = 6–7 per treatment). Fetal semitendinosus was cryosectioned and immunostained for detection of Pax7(+) cells followed by image analysis. Data were analyzed using the MIXED procedure in SAS. Semitendinosus from RES lambs had a greater number of Pax7(+) cells but similar total cell numbers to CON offspring, resulting in a greater percentage of Pax7(+) cells at d90 of gestation (CON: 13.22 ± 0.74%; RES: 16.01 ± 0.74%, P = 0.01). At day 130, there was no difference in the percentage of Pax7(+) cells between dietary treatment groups (CON-CON: 7.88 ± 0.80%; CON-RES: 6.34 ± 0.74%; RES-RES: 7.82 ± 0.74%; RES-CON: 6.87 ± 0.74%; P > 0.17). The percentage of Pax7(+) cells decreased from day 90 to day 130, regardless of dietary treatment (P < 0.0001). In summary, restricted maternal nutrition may delay progenitor cell differentiation at mid-gestation.

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Characterisation of acyltransferase activity in ovine placental tissue during pregnancy and at the time of labour

Journal of Endocrinology ◽

10.1677/joe.0.1480241 ◽

1996 ◽

Vol 148 (2) ◽

pp. 241-247

Author(s):

M H Wong ◽

G E Rice

Keyword(s):

Arachidonic Acid ◽

Placental Tissue ◽

Late Gestation ◽

Acyltransferase Activity ◽

Ovine Placenta ◽

Biochemical Mechanisms ◽

Group 2 ◽

Acyl Coenzyme A ◽

Eicosanoid Formation

Abstract Although it is well established that the formation of eicosanoids by ovine intrauterine tissues increases during pregnancy and at the time of labour, the biochemical mechanisms involved remain to be clearly established. In this study, we tested the hypothesis that the gestational and labour-associated increases in eicosanoid formation are associated with a reduction in the activity of the reacylating enzyme, acyl Coenzyme A lysophosphatide acyltransferase (LAT). To evaluate this proposal, in vitro LAT activity was quantified in ovine placenta (cotyledons) obtained during pregnancy (85–147 days of gestation and at the time of labour). Ovine placental LAT increased from 1·81 ± 0·06 nmol/min per mg protein at 85 days of gestation to 2·34 ± 0·10 nmol/min per mg protein at 142 days of gestation (P<0·005, n=15). The apparent Km did not vary significantly between the 85- and 142-day groups. Vmax, however, was significantly greater in the late-gestation group (2·98 ± 0·02 nmol/min per mg protein) than in the mid-gestation group (2·38 ± 0·13 nmol/min per mg protein, P<0·05). In association with labour, placental LAT activity decreased by 16% (1·96 ± 0·13 nmol/min per mg protein) when compared with that observed in tissue obtained from the non-labouring ewe (P<0·01). The data obtained are consistent with the hypothesis that changes in LAT activity in ovine placenta do not contribute to the gestational increase in prostaglandin formation, but a contribution to the labour-associated increase in non-esterified arachidonic acid availability and eicosanoid formation cannot be negated. Journal of Endocrinology (1996) 148, 241–247

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Ultrastructural Changes in the Mammary Epithelial Cell Population During Neoplastic Development Induced by A Chemical Carcinogen.

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100091238 ◽

1976 ◽

Vol 34 ◽

pp. 250-251 ◽

Cited By ~ 2

Author(s):

J. Russo ◽

W. Isenberg ◽

M. Ireland ◽

I.H. Russo

Keyword(s):

Mammary Gland ◽

Cell Population ◽

Virgin Female ◽

Histological Change ◽

Mammary Epithelial ◽

Female Rats ◽

Ultrastructural Changes ◽

Post Inoculation ◽

Chemical Carcinogen ◽

Sprague Dawley

The induction of rat mammary carcinoma by the chemical carcinogen DMBA is used as a model for the study of the human disease (1). We previously described the histochemical changes that occur in the mammary gland of DMBA treated animals before the earliest manifested histological change, the intraductal proliferation (IDP), was observed (2). In the present work, we demonstrate that a change in the stable cell population found in the resting mammary gland occurs after carcinogen administration.Fifty-five day old Sprague-Dawley virgin female rats were inoculated intragastrically with 20mg of 7,12-dimethylbenz(a)anthracene (DMBA) in 1ml sesame oil. Non-inoculated, age-matched females were used as controls. Mammary glands from control and inoculated rats were removed weekly from the time of inoculation until 60 days post-inoculation. For electron microscopy, the glands were immersed in Karnovsky's fixative, post-fixed in 1% OsO4, dehydrated, and embedded in an Epon-Araldite mixture. Thick (lμ) sections were stained with 1% toluidine blue and were used for selecting areas for ultrastructural study.

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