Effects of early gestation GH administration on placental and fetal development in sheep

Wright, Casey D.; Orbus, Ryan J; Regnault, Timothy R. H.; Anthony, Russell V.

doi:10.1677/joe-07-0481

Cited by 6 publications

(8 citation statements)

References 35 publications

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“…2 by methods previously described by this laboratory (Warren et al, 1990;Kappes et al, 1992). The tcRNA was subjected to quantitative real-time reverse transcriptase-PCR (qPCR) analysis, as previously described (Erikson-Hagen et al, 2005;Wright et al, 2008). Briefl y, the primer sets listed in Table 2 were used to generate intron-spanning cDNA amplicons for sheep IGF1, IGF2, IGF1 receptor (IGF1R), IGF2 receptor (IGF2R), insulin receptor (INSR), and ribosomal protein subunit 15 (RPS15), which were sequenced to verify authenticity and used to generate standard curves spanning from 10 to 1 × 10 6 pg starting quantity.…”

Section: Liver Mrna Analysismentioning

confidence: 99%

“…After 40 cycles of qPCR, with a fl uorescence measurement after each cycle, a melting curve analysis was initiated at 55ºC, with fl uorescence measured at 0.5°C increments until 95°C. Relative expression of IGF1, IGF2, IGF1R, IGF2R, and INSR was determined by dividing the starting quantity of the mRNA of interest by the starting quantity of RPS15 (Erikson-Hagen., 2005;Wright et al, 2008).…”

Section: Liver Mrna Analysismentioning

confidence: 99%

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Effects of overfeeding naturally-mated adolescent ewes on maternal, fetal, and postnatal lamb growth1

Peel

Eckerle

Anthony

2012

Journal of Animal Science

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The objective of this study was to evaluate the effects of overfeeding naturally-mated adolescent ewes (Ovis aries) on maternal, fetal, and postnatal lamb growth, hormone concentrations, and lamb carcass characteristics. Two experiments were conducted in which singleton-bearing adolescent ewes were fed a diet containing 2.72 Mcal/kg ME at a rate which met NRC gestational age requirements (MN; n = 10 in Exp. 1, n = 7 in Exp. 2) or were fed the same diet ad libitum (15% refusal rate) throughout gestation (HN; n = 7 in Exp. 1, n = 6 in Exp. 2). Ewe BW was greater (P < 0.05) for HN than MN ewes beginning on 75 d and 52 d of gestation for Exp. 1 and 2, respectively. Final BCS was greater (P ≤ 0.05) for HN than MN ewes in both experiments; 3.5 vs. 3.0, respectively, for Exp. 1, and 4.8 vs. 2.9, respectively, for Exp. 2. Fasting maternal blood insulin concentrations were greater (P ≤ 0.05) in HN ewes near term (135 d of gestation), whereas fasting maternal glucose concentrations were greater (P ≤ 0.05) during most of the second half of gestation in HN ewes, for both experiments. Gestation length did not differ (P = 0.69) between treatments in Exp. 1, but in Exp. 2, HN ewes had shorter (P = 0.01) gestation lengths (144 vs. 149 d) and had increased (P = 0.002) dystocia scores. Fetal abdominal circumference was greater (P < 0.05) in lambs from MN than HN ewes at 97 d of gestation in Exp. 1 (20.8 vs. 17.4 cm) but did not differ (P = 0.94) between treatments at 95 d of gestation in Exp. 2 (averaging 20.5 cm). There were no differences (P ≥ 0.15) in lamb BW, abdominal circumference, crown-rump length, and biparietal distance at birth; or in postnatal BW and plasma concentrations of glucose, insulin, and lactate in either experiment. There were no differences (P ≥ 0.18) in HCW, dressing percentage, LM area, fat thickness, or KPH between treatments in Exp. 2. Although there was no difference (P ≥ 0.31) between treatments in concentrations of IGF1 or IGF2 mRNA in liver samples collected at harvest, lambs from MN ewes had greater (P ≤ 0.05) concentrations of IGF1R and INSR mRNA, suggesting long-term effects of maternal diet on postnatal hepatic function. In conclusion, excess nutrition during gestation in naturally-mated adolescent ewes did not affect birth weight or postnatal performance of offspring.

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Section: Liver Mrna Analysismentioning

confidence: 99%

Section: Liver Mrna Analysismentioning

confidence: 99%

Effects of overfeeding naturally-mated adolescent ewes on maternal, fetal, and postnatal lamb growth1

Peel

Eckerle

Anthony

2012

Journal of Animal Science

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“…However, in later pregnancy, increasing maternal circulating IGF‐I appears to have no immediate effect on maternal body composition or fetal weight (Harding et al 1997). The extent of IGF‐I actions on the mother is dependent on gestational age, maternal age and nutrition, and whether the pregnancy is a singleton or twin (Table 1: Costine et al 2005; Wallace et al 2006 a ; Kenyon et al 2007; Wright et al 2008; Koch et al 2010). Like the pig, maternal IGF‐I may have most benefit on ovine fetal growth in adverse maternal environments.…”

Section: Maternal Metabolism and Nutrient Partitioningmentioning

confidence: 99%

The neglected role of insulin‐like growth factors in the maternal circulation regulating fetal growth

Sferruzzi‐Perri

Owens

Pringle

et al. 2010

The Journal of Physiology

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Maternal insulin-like growth factors (IGFs) play a pivotal role in modulating fetal growth via their actions on both the mother and the placenta. Circulating IGFs influence maternal tissue growth and metabolism, thereby regulating nutrient availability for the growth of the conceptus. Maternal IGFs also regulate placental morphogenesis, substrate transport and hormone secretion, all of which influence fetal growth either via indirect effects on maternal substrate availability, or through direct effects on the placenta and its capacity to supply nutrients to the fetus. The extent to which IGFs influence the mother and/or placenta are dependent on the species and maternal factors, including age and nutrition. As altered fetal growth is associated with increased perinatal morbidity and mortality and a greater risk of developing degenerative diseases in adult life, understanding the role of maternal IGFs during pregnancy is essential in order to identify mechanisms underlying altered fetal growth and offspring programming.

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“…Administration of GH daily at 0.2 mg/kg from d 35 to 55 had no effect on fetal weight by the end of treatment and did not affect fetal weight at d 135 of gestation (Wright et al, 2008). We interpret this to mean that whatever programming effect GH treatment has during very early gestation, the window of opportunity to impart that program is no longer open by as early as d 35 of gestation.…”

Section: Discussionmentioning

confidence: 86%

“…We interpret this to mean that whatever programming effect GH treatment has during very early gestation, the window of opportunity to impart that program is no longer open by as early as d 35 of gestation. Wright et al (2008) chose d 35 to 55 to administer GH because this is the period of gestation in which the placenta is producing GH. However, increases in maternal pituitary GH or peripheral IGF-I during the first 4 wk of gestation may be more critical to affecting the growth of the fetoplacental unit than the GH produced for 20 d by the endometrium during wk 5 to 8 of gestation.…”

Section: Discussionmentioning

confidence: 99%

Periconceptional growth hormone treatment alters fetal growth and development in lambs1

Koch

Wilmoth

Wilson

2010

Journal of Animal Science

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Research in the area of fetal programming has focused on intrauterine growth restriction. Few studies have attempted to examine programming mechanisms that ultimately lead to lambs with a greater potential for postnatal growth. We previously demonstrated that treatment of ewes with GH at the time of breeding led to an increase in birth weight. Therefore, the objective of this study was to determine the effects of a single injection of sustained-release GH given during the periconceptional period on fetal growth and development and to determine if the GH axis would be altered in these offspring. Estrus was synchronized using 2 injections of PGF(2alpha); at the time of the second injection, ewes assigned to treatment were also given an injection of sustained-release GH. A maternal jugular vein sample was taken weekly to analyze IGF-I as a proxy for GH to estimate the duration of the treatment effect. In ewes treated with GH, IGF-I increased (P < 0.05) by wk 1 and remained elevated until wk 4 postinjection. Lambs were weighed, crown-rump length and abdominal girth were determined, and a plasma sample was collected. In a subset of male lambs, liver, heart, and brain weights were obtained, as well as left and right ventricular wall thicknesses. On postnatal d 100, a subset of ewe lambs were weighed and challenged with an intravenous injection of GHRH. Lambs from treated ewes had increased (P < 0.05) birth weight and abdominal girth compared with control lambs; however, there was no difference in crown-rump length. Expression of GH receptor and IGF-I were increased (P < 0.05) in lambs gestated by GH-treated ewes compared with control ewes. The left ventricular wall was thinner (P < 0.05) from lambs in the GH-treated group compared with control lambs. On postnatal d 100, those ewe lambs born to ewes treated with GH continued to be heavier (P < 0.05) and had no IGF-I response to GHRH challenge. In conclusion, treating ewes with a single injection of GH appeared to alter fetal growth and development. Lambs born to ewes treated with GH were larger at birth and had altered organ development, which may indicate that early maternal GH treatment may lead to permanent changes in the developing fetus. The ewe lambs maintained their growth performance to at least 100 d of postnatal life and appeared to have an altered GH axis, as demonstrated by the altered response to GHRH.

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Effects of early gestation GH administration on placental and fetal development in sheep

Cited by 6 publications

References 35 publications

Effects of overfeeding naturally-mated adolescent ewes on maternal, fetal, and postnatal lamb growth1

Effects of overfeeding naturally-mated adolescent ewes on maternal, fetal, and postnatal lamb growth1

The neglected role of insulin‐like growth factors in the maternal circulation regulating fetal growth

Periconceptional growth hormone treatment alters fetal growth and development in lambs1

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