Fetal insulin-like growth factor (IGF)-I and IGF-II are regulated differently by glucose or insulin in the sheep fetus

Oliver, Mark; Harding, JE; Bh, Breier; Gluckman, P. D.

doi:10.1071/rd9960167

Cited by 73 publications

(45 citation statements)

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“…Previous studies have suggested that fetal IGF-I and IGF-II are independently regulated in sheep fetal circulation and show a different expression pattern (Fowden and Silver, 1995;Oliver et al, 1996). Expression of the IGF-I and IGF-II genes depend on the origin of the cells and their development stage (Wang et al, 2011).…”

Section: Discussionmentioning

confidence: 99%

Association between DLK1 and IGF-I gene expression and meat quality in sheep

Su¹,

Sun²,

Li³

et al. 2014

Genet. Mol. Res.

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ABSTRACT. The aim of the present study was to detect delta-like 1 homolog (DLK1) and insulin-like growth factor-I (IGF-I) gene expression in the longissimus dorsi of Hu sheep at different growth stages and study the association between these genes and meat quality. The diameter and density of muscle fibers and tenderness of the longissimus dorsi were measured. Growth stage, but not sex, significantly affected DLK1 and IGF-I expression. DLK1 and IGF-I expression in the sheep longissimus dorsi gradually increased with growth, but also decreased during some periods. These results suggest that different growth stages significantly affect DLK1 and IGF-I gene expression in sheep muscle tissue. The expression of DLK1 and IGF-I genes were positively and significantly (P < 0.01) correlated with muscle fiber diameter and muscle fiber shear stress, and negatively and significantly (P < 0.01) correlated with muscle fiber density. Muscle fiber diameter was positively and significantly (P < 0.01) correlated with muscle fiber shear stress, and negatively and significantly (P < 0.01) correlated with muscle fiber density. In addition,

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Section: Discussionmentioning

confidence: 99%

Association between DLK1 and IGF-I gene expression and meat quality in sheep

Su¹,

Sun²,

Li³

et al. 2014

Genet. Mol. Res.

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“…The major hormones regulating foetal growth in late gestation appear to be insulin and IGFs (Fowden, 1989;Harding et al, 1993), which regulate foetal nutrient uptake and the distribution of nutrients in the foetus. In turn, they are regulated by foetal nutrient supplies (Oliver et al, , 1996. Therefore, reducing the glucose supply to the foetus decreases circulating insulin and IGF concentrations and, consequently, reduces foetal growth.…”

Section: Foetal Growthmentioning

confidence: 99%

Foetal and neonatal energy metabolism in pigs and humans: a review

Mota-Rojas¹,

Orozco-Gregorio²,

Villanueva-García³

et al. 2011

Vet. Med. - Czech

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ABSTRACT:The aim of this review was to elaborate a conceptual framework of the most important aspects of the main biochemical processes of synthesis and breakdown of energy substrates that human and pig foetuses and newborns can use during the transition from foetus to newborn. Under normal physiological conditions, the growth and development of the foetus depends upon nutrients such as glucose, lipids and amino acids. In addition to the maternal and foetal status, genetic factors are also reported to play a role. The main function of the placenta in all species is to promote the selective transport of nutrients and waste products between mother and foetus. This transport is facilitated by the close proximity of the maternal and foetal vascular systems in the placenta. The foetus depends on the placental supply of nutrients, which regulates energy reserves by means of glycogen storage. Also, the synthesis of foetal hepatic glycogen guarantees energy reserves during perinatal asphyxia or maternal hypoglycaemia. However, the foetus can also obtain energy from other resources, such as gluconeogenesis from the intermediary metabolism of the Krebs cycle and most amino acids. Later, when the placental glucose contribution ends during the transition to the postnatal period, the maturation of biological systems and essential metabolic adaptations for survival and growth is required. The maintenance of normoglycaemia depends on the conditions that determine nutrient status throughout life: the adequacy of glycogen stores, the maturation of the glycogenolytic and gluconeogenic pathway, and an integrated endocrine response.

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“…However, it seems unlikely that such a large reduction in weight would not be accompanied by functional impairment. Both the fetal and postnatal kidney express GH and IGF-receptors (Feld & Hirschberg 1996, Oliver et al 1996 and postnatally, kidney growth and function is very sensitive to circulating GH. Compensatory renal growth after unilateral nephrectomy (Flyvbjerg et al 1999b) and renal hypertrophy in diabetes (Flyvbjerg et al 1999a) has been shown to be GH dependent and acromegaly and GH therapy are associated with increased glomerular filtration rate and renal plasma flow in man (Ogle et al 1992).…”

Section: Igf-i Concentrations In the Fetusmentioning

confidence: 99%

Chronic pulsatile infusion of growth hormone to growth-restricted fetal sheep increases circulating fetal insulin-like growth factor-I levels but not fetal growth

Bauer

Breier²,

Bloomfield³

et al. 2003

Journal of Endocrinology

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Intra-uterine growth restriction (IUGR) is a major cause of perinatal mortality and morbidity. Postnatally, growth hormone (GH) increases growth, increases circulating insulin-like growth factor (IGF)-I levels, and alters metabolism. Our aim was to determine if GH infusion to IUGR fetal sheep would alter fetal growth and metabolism, and thus provide a potential intra-uterine treatment for the IUGR fetus.We studied three groups of fetuses: control, IUGR+ vehicle and IUGR+GH (n=5 all groups). IUGR was induced by repeated embolisation of the placental vascular bed between 110 and 116 days of gestation (term=145 days). GH (3·5 mg/kg/day) or vehicle was infused in a pulsatile manner from 117 to 127 days of gestation.Embolisation reduced fetal growth rate by 25% (P<0·01) and reduced the weight of the fetal liver (20%), kidney (23%) and thymus (31%; all P<0·05). GH treatment further reduced the weight of the fetal kidneys (32%) and small intestine (35%; both P<0·04), but restored the relative weight of the fetal thymus and liver (P<0·05). Embolisation decreased fetal plasma IGF-I concentrations (48%, P<0·001) and increased IGF binding protein 1 (IGFBP-1) concentrations (737%, P<0·002). GH treatment restored fetal plasma IGF-I concentrations to control levels, while levels in IUGR+vehicle fetuses stayed low (P<0·05 vs control). IGFBP-1 and IGFBP-2 concentrations were about sevenfold lower in amniotic fluid than in fetal plasma, but amniotic and plasma concentrations were closely correlated (r=0·75, P<0·0001 and r=0·55 P<0·0001 respectively). Embolisation transiently decreased fetal blood oxygen content (40%, P<0·002), and increased blood lactate concentrations (213%, P<0·04). Both returned to pre-embolisation levels after embolisation stopped, but blood glucose concentrations declined steadily in IUGR+vehicle fetuses. GH treatment maintained fetal blood glucose concentrations at control levels.Our study shows that GH infusion to the IUGR fetal sheep restores fetal IGF-I levels but does not improve fetal growth, and further reduces the fetal kidney and intestine weights. Thus, fetal GH therapy does not seem a promising treatment stratagem for the IUGR fetus.

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Fetal insulin-like growth factor (IGF)-I and IGF-II are regulated differently by glucose or insulin in the sheep fetus

Cited by 73 publications

References 0 publications

Association between DLK1 and IGF-I gene expression and meat quality in sheep

Association between DLK1 and IGF-I gene expression and meat quality in sheep

Foetal and neonatal energy metabolism in pigs and humans: a review

Chronic pulsatile infusion of growth hormone to growth-restricted fetal sheep increases circulating fetal insulin-like growth factor-I levels but not fetal growth

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