Maternal growth hormone treatment increases placental diffusion capacity but not fetal or placental growth in sheep

Harding, Jane E; Evans, P C; Gluckman, Peter D.

doi:10.1016/s0143-4004(96)90120-4

Cited by 18 publications

(27 citation statements)

References 3 publications

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“…As outlined in the Introduction, previous studies in sheep using similar doses of bGH have failed to influence the growth of the uteroplacenta and have had variable effects on fetal weight [12,16,17]. However, these studies were carried out in adult ewes with normally growing fetuses and were confounded by litter size.…”

Section: Discussionmentioning

confidence: 99%

“…Similarly, GH deficiency in rat dams is associated with impaired fetal growth [11]. GH does not cross the placenta, but increased maternal GH concentrations may influence fetal growth by inhibiting the lipogenic action of insulin and increasing glucose concentrations in the maternal circulation and/or by increasing placental capacity to transfer nutrients to the fetus [12]. Alternatively, GH of pituitary or extrapituitary origin may influence the growth of the uteroplacenta directly or indirectly via the IGF system.…”

Section: Introductionmentioning

confidence: 99%

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Maternal Growth Hormone Treatment from Day 35 to 80 of Gestation Alters Nutrient Partitioning in Favor of Uteroplacental Growth in the Overnourished Adolescent Sheep1

Wallace¹,

Milne²,

Aitken³

2004

Biology of Reproduction

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Overnourishing the pregnant adolescent ewe promotes maternal tissue synthesis at the expense of placental growth and leads to a major reduction in lamb birth weight at term. Growth hormone (GH) secretion is attenuated in these overnourished dams and the maternal somatotrophic axis may play a key role in coordinating nutrient usage in the pregnant adolescent. Thus we investigated whether increasing maternal GH during the period of rapid placental proliferation alters nutrient partitioning between the maternal, placental, and fetal tissues as assessed at Day 81 of gestation. Adolescent recipient ewes were implanted with singleton embryos, derived from superovulated dams and a single sire on Day 4 postestrus. Thereafter, the ewes were offered either a high (H) or moderate intake (M) of the same complete diet. From Day 35 to 80 of gestation, ewes were either injected twice daily (s.c. at 0800 and 1800 h) with recombinant bovine GH (bGH, 0.14 mg/kg live weight/day) or remained untreated (n = 8 ewes per group). Maternal concentrations of GH, insulin, insulin-like growth factor (IGF-1), glucose, and non-esterified fatty acids (NEFAs) were higher, and leptin secretion lower, in bGH-treated dams from both nutritional groups. Maternal body weight gain was higher in H versus M groups and was independent of bGH treatment. Treatment with bGH reduced relative perirenal and carcass fat deposition and increased carcass protein content in both H and M dams. Uteroplacental mass (uterus + placentomes + fetal membranes) averaged 1099, 1069, 1112, and 1754 g in M, H, M+GH, and H+GH groups. This significant increase in uteroplacental development in the H+GH group was associated with higher fetal kidney and liver weights and elevated fetal insulin, glucose, and lactate concentrations. Treatment with bGH also induced polyhydramnios in the H group. The transplacental glucose gradient was increased twofold in the H+GH group but placental GLUT- 1 and GLUT-3 expression was unaffected. In conclusion, administration of GH during the period of rapid placental proliferation alters endocrine status and thus nutrient partitioning in the overnourished adolescent dam in favor of uteroplacental and fetal growth. It remains to be established whether these effects are due wholly to alterations in maternal metabolism or if they also reflect an effect of bGH and/or the IGF system at the level of the uteroplacenta.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Maternal Growth Hormone Treatment from Day 35 to 80 of Gestation Alters Nutrient Partitioning in Favor of Uteroplacental Growth in the Overnourished Adolescent Sheep1

Wallace¹,

Milne²,

Aitken³

2004

Biology of Reproduction

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“…Ewes were anesthetized during surgery with halothane (1.5-2.5%) in oxygen, and fetal arterial, venous, and amniotic catheters were placed as described previously (10). To assess fetal growth, a catheter to measure changes in fetal girth over time was sutured to each side of the fetal chest from spine to sternum (9,18). After closure of the uterus, the utero-ovarian vein and maternal arterial and venous catheters were placed.…”

Section: Methodsmentioning

confidence: 99%

Chronic alterations in ovine maternal corticosteroid levels influence uterine blood flow and placental and fetal growth

Jensen

Wood

Keller‐Wood

2005

American Journal of Physiology-Regulatory, Integrative and Comp

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Previous work from this laboratory demonstrated that the elevation of maternal plasma corticosteroid concentrations during pregnancy is important for the support of fetal development. Reducing ovine maternal plasma cortisol concentrations to nonpregnant levels stimulates homeostatic responses that defend fetal blood volume. The present study was designed to test the hypothesis that chronic decreases or increases in maternal plasma cortisol concentration alter uterine and placental blood flow and morphology. Three groups of pregnant ewes and their fetuses were chronically catheterized and studied: ewes infused with cortisol (1 mg.kg(-1).day(-1); high cortisol), ewes adrenalectomized and underreplaced with cortisol (0.5 mg.kg(-1).day(-1); low cortisol), and control ewes. The normal increment in uterine blood flow between 120 and 130 days was eliminated in the low-cortisol ewes; conversely, uterine blood flow was increased in the high-cortisol group compared with the control group. Fetal arterial blood pressure was increased in the high-cortisol group compared with controls, but there was no increase in fetal arterial pressure from 120 to 130 days of gestation in the low-cortisol group. The fetuses of both low-cortisol and high-cortisol groups had altered placental morphology, with increased proportions of type B placentomes, and overall reduced fetal placental blood flow. The rate of fetal somatic growth was impaired in both low-cortisol and high-cortisol groups compared with the fetuses in the intact group. The results of this study demonstrate that maternal plasma cortisol during pregnancy is an important contributor to the maternal environment supporting optimal conditions for fetal homeostasis and somatic growth.

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“…Animal studies related to species-specific PGH secretion are sparse. Studies in sheep, the only other mammal known to have a growth hormone variant of presumed placental origin [142,143], suggested an effect of GH injections on placental diffusion capacity [144,145]. In particular, GH infusion in late gestation resulted in larger fetuses [145].…”

Section: Physiological Effects In Vivomentioning

confidence: 99%

Aspects of placental growth hormone physiology

Fuglsang

Ovesen

2006

Growth Hormone & IGF Research

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Maternal growth hormone treatment increases placental diffusion capacity but not fetal or placental growth in sheep

Cited by 18 publications

References 3 publications

Maternal Growth Hormone Treatment from Day 35 to 80 of Gestation Alters Nutrient Partitioning in Favor of Uteroplacental Growth in the Overnourished Adolescent Sheep1

Maternal Growth Hormone Treatment from Day 35 to 80 of Gestation Alters Nutrient Partitioning in Favor of Uteroplacental Growth in the Overnourished Adolescent Sheep1

Chronic alterations in ovine maternal corticosteroid levels influence uterine blood flow and placental and fetal growth

Aspects of placental growth hormone physiology

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