Insulin-like Growth Factor 2 cDNA Cloning and Ontogeny of Gene Expression in the Liver of the Marsupial Brushtail Possum (Trichosurus vulpecula)

Saunders, ME; Gemmell, R. T.; Curlewis, J. D.

doi:10.1006/gcen.2000.7581

Cited by 3 publications

(4 citation statements)

References 35 publications

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“…Here we show that liver GHR and IGF-I mRNA expression are low early in pouch life, do not show large and sustained increases until 125 days post-partum and are similar to those in adult liver by 150 days post-partum. In contrast, we have previously shown that IGF-II gene expression is high from 12 through to 150 days post-partum and significantly above that of the adult for this entire period (Saunders et al 2001). These results suggest that IGF-II, which is regarded as a fetal growth factor in eutherian mammals, could play a similar role in post-natal growth of marsupials during the first half of pouch life when GHR and IGF-I expression is low.…”

Section: Discussionmentioning

confidence: 60%

“…Reactions for all genes contained 0·5 µl ss cDNA, 0·5 µM each primer, 0·2 mM each dNTP, 2 mM MgCl 2 and 1·3 U Taq DNA polymerase (Biotech International, Perth, Australia) in 50 µl 1 Taq reaction buffer (Biotech International). PCR products were cloned and sequenced as previously described (Saunders et al 2001). For each cDNA, two clones were sequenced in both directions.…”

Section: Pcr Cloning Of Possum Ghr Igf-i and Igfbp-3mentioning

confidence: 99%

“…This method has been previously described by us for quantification of IGF-II mRNA expression in possum liver (Saunders et al 2001). Extraction of total RNA from liver tissue and preparation of ss cDNA were performed as described above except that 3 µg total RNA were used in the RT reaction.…”

Section: Semi-quantitative Rt-pcr For Ghr Igf-i and Igfbp-3mentioning

confidence: 99%

“…GHR, IGF-I and IGFBP-3 mRNA expression in liver from pouch young (12-150 days post-partum) and adults (n=4/group) was then determined and expressed relative to -actin, which did not show changes between age groups (Saunders et al 2001). The precision of the semi-quantitative PCR was assessed on five replicates of an adult liver cDNA sample.…”

Section: Semi-quantitative Rt-pcr For Ghr Igf-i and Igfbp-3mentioning

confidence: 99%

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The GH/IGF-I axis in the brushtail possum (Trichosurus vulpecula) pouch young

Saunders¹,

Gemmell²,

Curlewis³

2003

Journal of Endocrinology

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Plasma and pituitary GH concentrations and liver GH receptor (GHR), IGF-I and IGF-binding protein-3 (IGFBP-3) mRNA expression were determined in brushtail possum (Trichosurus vulpecula) pouch young aged 12-150 days post-partum and in adults. Mean plasma GH concentrations were highest, measuring around 150 ng/ml, from 12 to 100 days post-partum, and thereafter declined so that by 150 days post-partum levels were not significantly different from those in adults (10·8 1·8 ng/ml (S.E.M.)). In contrast to plasma levels, pituitary GH content increased markedly throughout pouch life, with an 87-fold increase between 12 and 150 days post-partum. However, when expressed per gram body weight, pituitary content was relatively constant between 25 and 150 days post-partum, indicating that the decline in plasma GH after 100 days post-partum was not due to decreased synthesis and/or storage of GH in the pituitary gland. Expression of GHR, IGF-I and IGFBP-3 mRNAs was determined by semi-quantitative RT-PCR. Liver GHR and IGF-I mRNA expression were low at 12 and 25 days post-partum and did not show sustained and significant increases (P<0·05) until 125 and 150 days post-partum. IGFBP-3 expression was also low at 12 days post-partum but then increased rapidly to a maximum at 50 days post-partum and thereafter declined. For all three mRNAs, liver expression at day 150 was not significantly different from that in adults. These patterns of gene expression for GHR and IGF-I suggest that the possum liver is resistant to the high plasma GH concentrations during early pouch life and in this way is similar to the fetal liver of some eutherian mammals.

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Section: Discussionmentioning

confidence: 60%

Section: Pcr Cloning Of Possum Ghr Igf-i and Igfbp-3mentioning

confidence: 99%

Section: Semi-quantitative Rt-pcr For Ghr Igf-i and Igfbp-3mentioning

confidence: 99%

Section: Semi-quantitative Rt-pcr For Ghr Igf-i and Igfbp-3mentioning

confidence: 99%

See 2 more Smart Citations

The GH/IGF-I axis in the brushtail possum (Trichosurus vulpecula) pouch young

Saunders¹,

Gemmell²,

Curlewis³

2003

Journal of Endocrinology

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Insulin-Like Growth Factors (IGFs) in Vertebrate Phylogenesis. Comparative Analysis of the IGF-II Domain Binding to the Mannose-6-Phosphate IGF-II-Receptor

Kolychev

2005

J Evol Biochem Phys

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The tammar wallaby: a non-traditional animal model to study growth axis maturation

Hetz

Menzies

Shaw

et al. 2019

Reprod. Fertil. Dev.

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Maturation of the growth hormone (GH)/insulin-like growth factor 1 (IGF1) axis is a critical developmental event that becomes functional over the peripartum period in precocial eutherian mammals such as sheep. In mice and marsupials that give birth to altricial young, the GH/IGF1 axis matures well after birth, suggesting that functional maturation is associated with developmental stage, not parturition. Recent foster-forward studies in one marsupial, the tammar wallaby (Macropus eugenii), have corroborated this hypothesis. ‘Fostering’ tammar young not only markedly accelerates their development and growth rates, but also affects the timing of maturation of the growth axis compared with normal growing young, providing a novel non-traditional animal model for nutritional manipulation. This review discusses how nutrition affects the maturation of the growth axis in marsupials compared with traditional eutherian animal models.

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Insulin-like Growth Factor 2 cDNA Cloning and Ontogeny of Gene Expression in the Liver of the Marsupial Brushtail Possum (Trichosurus vulpecula)

Cited by 3 publications

References 35 publications

The GH/IGF-I axis in the brushtail possum (Trichosurus vulpecula) pouch young

The GH/IGF-I axis in the brushtail possum (Trichosurus vulpecula) pouch young

Insulin-Like Growth Factors (IGFs) in Vertebrate Phylogenesis. Comparative Analysis of the IGF-II Domain Binding to the Mannose-6-Phosphate IGF-II-Receptor

The tammar wallaby: a non-traditional animal model to study growth axis maturation

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