• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제31권5호
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• pp.363-369
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• 2005

Purpose: To determine the role of Insulin-like Growth Factor-I (IGF-I) in the regulation of Vascular Endothelial Growth Factor (VEGF) expression in MG-63 cells and then to find the mechanism b which this regulation occurs. Materials and methods: MG-63 cells were grown to confluence in 60-mm dishes. To determine the effects of IGF-I on expression of VEGF mRNA according to time and concentration, the cells were treated with 10 nM IGF-I, following isolation of total RNA and Northern blot analysis after 1, 2, 4, 8, 12, 24 hours and after 2 hours of treatment with 0.5, 2, 10, 25, 50 nM IGF-I respectively, isolation of total RNA and Northern blot analysis were followed. To determine the mechanism of action of IGF-I, inhibitors such as hydroxyurea $(76.1\;{\mu}g/ml)$, actinomycin D $(2.5\;{\mu}g/ml)$, cycloheximide $(10\;{\mu}g/ml)$ were added 1 hour after treatment of 10 nM IGF-I. Results: 1. the expression of VEGF mRNA was increased with treatment of IGF-I. 2. The expression of VEGF mRNA was increased according to time-and concentration dependent manner of IGF-I. 3. The effect of IGF-I was decreased by hydroxyuera, actinomycin D, but not by cycloheximide. Conclusion: IGF-I regulate the expression of VEGF mRNA in the level of DNA synthesis and transcription. These results could suggest that IGF-I plays an important role in angiogenesis in the process of new bone formation and remodeling.

• Reproductive and Developmental Biology
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• 제30권2호
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• pp.93-97
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• 2006

To study the signaling effect of insulin-like growth factor-I(IGF-1), transgenic mice containing IGF-1 Receptor (IGF-1R) cDNA fused to metallothionein promoter were produced by DNA microinjection into the pronucleus of mouse zygote. Three founders were produced with transgenic mice containing IGF-1R gene. Transgenic mice lines contained approximately $4{\sim}20$ copies of transgenes per cell and transmission of this gene into the progeny with Mendelian manner were determined. The founder mice were mated with normal mice to produce $F_1$ mice and then $F_2$ mice. Transmission rates of IGF-1R transgene in the progeny mice were $25{\sim}60%$ in $F_1$ generation and $40{\sim}50%$ in $F_2$ generation. The mRNA expression of IGF-1R transgene in liver was analyzed using RT-PCR for IGF-1R gene in liver. When body weights of transgenic pups were measured during 4, 10 and 14 weeks after birth, IGF-1R transgenic mice grew faster than non transgenic littermates. This study indicated that growth regulation by IGF-1 signaling through IGF-1R can be elucidated using IGF-1R transgenic mice.

• Molecules and Cells
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• 제28권3호
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• pp.189-194
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• 2009

The modulating effect of IGF-I on the regulation of AR gene expression and activation in skeletal muscle cells remains poorly understood. In this study, the effects of IGF-I treatment on AR induction and activation in the absence of AR ligands were examined. Differentiating C2C12 cells were treated with different concentrations (0-250 ng/ml) of IGF-I or for various periods of time (0-60 min) of 250 ng/ml IGF-I. Treatment of C2C12 cells with IGF-I resulted in a dose- and time-dependent increase in total AR and phosphorylated AR (Ser 213). IGF-I treatment also led to significantly increased AR mRNA expression when compared with the control. The levels of skeletal ${\alpha}-actin$ and myogenin mRNA, known target genes of AR, were also significantly upregulated after 5 or 10 min of treatment with IGF-I. Confocal images revealed that IGF-I stimulated nuclear localization of AR in the absence of ligands. In addition, an electrophoretic mobility shift assay indicated that IGF-I stimulated the AR DNA binding activity in a time-dependent manner. The present results suggest that IGF-I stimulates the expression and activation of AR by ligand-independent mechanism in differentiating C2C12 mouse skeletal muscle cells.

• Asian-Australasian Journal of Animal Sciences
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• 제11권3호
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• pp.245-248
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• 1998

The influence of refeeding either protein, carbohydrate or fat on hepatic insulin-like growth factor-I (IGF-I) mRNA level in chicks which had been fasted for 2 days was examined. The hepatic IGF-I mRNA was measured by ribonuclease protection assay. Fasting reduced hepatic IGF-I mRNA levels to less than half of those in the fed control. When chicks were refed either a control, protein or carbohydrate diet, IGF-I mRNA levels significantly increased to those in the fed control until 2 hours of refeeding. Refeeding of fat did not alter hepatic IGF-I mRNA levels. The significant correlation between liver weight and hepatic IGF-I gene expression suggests that when chicks are refed after 2-d fasting, the acute increase in hepatic IGF-I gene expression brought about after refeeding may be partly regulated by the increase in liver protein metabolism.

• 인터넷정보학회지
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• 제14권3호
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• pp.58-67
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• 2013

An essential prerequisite for negotiating governance of 'internet,' a world of 'end to end' nature, is to guarantee end-users' participation. Internet Governance Forum (IGF), the outcome of World Summit on the Information Society(WSIS) Tunis Agenda, has played an important role as a representative mulitistakeholder - based governance model, which puts emphasis on wide range participation of stakeholders. Notwithstanding multistakeholderism materialized in IGF has been challenged, IGF itself is a unique place for participation to broad internet governance discourse, as all voices get hearing grounded on openness, inclusion, and transparency, quite distinct from the multilateral negotiation based model such as 'Conference on Cyberspace.' Therefore civil society which represents end-users' interest, as a crucial stakeholder of internet governance, should establish more strategic and coordinated approach to IGF itself as well as reformation discourse of internet governance. In this regard, civil society groups of Korea, began with hosting workshops and Open Forum at the 2013 IGF in Bali, Indonesia. This report also describes the detailed activities of Korean civil society group in 2013 IGF.

• 생명과학회지
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• 제21권10호
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• pp.1385-1392
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• 2011

SOCS-3와 IGF-I은 근육의 분화 과정 및 근비대 기전에 있어 매우 중요한 조절자 역할을 하는 유전자 및 성장인 자이며, 최근 골격근에서 IGF-I과 SOCS-3 유전자의 상호작용에 관한 연구의 필요성이 제기되고 있다. 본 연구에서는 C2C12 myotube에서 IGF-I이 SOCS-3 유전자 발현에 미치는 영향에 대해 알아보기 위해 4일간 분화시킨 C2C12 myotube에 IGF-I을 다양한 농도(0-200 ng/ml) 및 시간(3-72 시간)에 따라 처리하였다. 그 결과 IGF-I이 SOCS-3 유전자의 단백질 발현을 시간 의존적으로 유의하게 증가시켰으며, 3 시간에서 mRNA 발현을 증가시키고, 시간이 지남에 따라 긴 시간에서는 농도 의존적으로 발현이 감소하였음을 알 수 있었다. 또한 면역형광 염색을 통해 IGF-I이 myotube에서 SOCS-3의 단백질을 발현 시켰음을 뚜렷하게 관찰 할 수 있었다. 위 결과들을 바탕으로 본 연구에서는 IGF-I의 처리가 분화된 근육 세포인 C2C12 myotube에서 SOCS-3 유전자 발현에 유의한 영향을 미쳤음을 증명하였다. 이러한 결과는 선행연구에서 보고한 운동이 SOCS-3 유전자 발현을 증가시킴에 있어서 IGF-I이 중추적인 역할을 한 것으로 생각된다. 그러나 IGF-I에 의한 SOCS-3 유전자 발현 조절 기전에 있어 관련 신호 전달체계 및 골격근 관련 유전자 발현에 미치는 영향에 관한 연구는 보다 더 이루어져야 할 것이라 사료된다.

• Asian-Australasian Journal of Animal Sciences
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• 제14권7호
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• pp.915-921
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• 2001

IGF-I is involved in the regulation of growth and differentiation in mammals, but its role as a modulator of growth and metabolism in poultry is poorly understood. And, no studies have so far been reported for the comparison between serum IGF-I concentration and body growth in the egg type or the dual purposes (meat and egg type) chicken including the Korean Native Ogol Chicken (KNOC). Therefore, in order to improve the body growth and meat production of the KNOC, this study was conducted for the identification of the polymorphism of IGF-I gene and for its possible association with both body weight and IGF-I concentration. The RFLP patterns for IGF-I gene were identified by the PstI restriction enzyme. The frequencies of +/+, +/-, and -/- genotype were 16.9%, 51.7%, and 31.4%, respectively. Any statistical significance was not observed in all variations except for sex variation (p<0.01) by covariate quadratic model. The significant effect of the IGF-I genotype on body weight by sex indicates that there are different physiological characteristics in gender. Although the body weights of male KNOCs in most ages were not significant, there was a tendency of KNOCs with +/+ IGF-I genotype to be heavier than those with any other genotypes. But all IGF-I genotypes in female did not influence on body weight. The ANOYA revealed no significant effects of IGF-I genotypes on serum IGF-I concentration but sex effect was highly significant on the IGF-I concentration at 20 and 40 weeks (p<0.01). Although the +/+ genotype, in gender, tended to express a higher IGF-I concentration than the other genotypes at all ages in males, a statistical difference among the genotypes was not found except for 60 weeks (p<0.05). Furthermore, since body weight and IGF-I genotypes are associated, it is possible to improve KNOC to a meat type breed if a continuous selection can be made for the body weight and/or IGF-I traits.

• 대한수의학회지
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• 제34권3호
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• pp.457-463
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• 1994

Insulin-like growth factor-I(IGF-I) plays an important role in the regulation of mammalian and poultry growth. IGF-I has many actions in different tissues, which include metabolic, mitogenic, and differentiative actions. IGF-I induces insulin-like effects - such as increased cell glucose uptake and glycogen sysnthesis, however several physiological actions of IGF-I may not have been identified yet. In order to investigate the effect on growth in broiler chicken treated with exogenous insulin-like growth factor-I, 30 chickens were injected $50{\mu}g$ reconbinant human IGF- I (rhIGF- I ) per kg body weight as experimental group and 30 ckickens saline subcutanously as control, 3 times according to ages from 2 to 35 days. We established radioimmunoassay method by which we can measure chicken IGF- I (cIGF- I ) as in rhIGF- I assay. The results obtained were as follows; 1) The dilution curve showed in parallelism between rhIGF- I and cIGF- I in the Sep-pak $C_{18}$ cartridge plasma extracts. 2) The body weight of broiler chicken were significantly increased at 31 days($1,176.50{\pm}99.79g$) and 35 days($1,252.84{\pm}125.21g$) of age in treatment groups, compared with control group($1,011.88{\pm}40.22g,\;1,111.32{\pm}153.67g$). The liver and kidney weights on 35 days$(35.24{\pm}5.18g,\;11.05{\pm}1.47g)$ were significantly higher in rhIGF- I treated group than control group($30.95{\pm}4.04g,\;10.01{\pm}1.60g$) 3) The plasma concentration of IGF- l and total protein in rhIGF- I treated group were $58.17{\pm}1.69ng/ml$, $3.75{\pm}0.62g/dl$ respectively compared with control group $45.70{\pm}1.64ng/ml$, $2.32{\pm}0.53g/dl$. The results suggest that exogenous rhIGF- I increased total body weight, liver and kidney weights in broiler chicken, and it may increase IGF- I and total protein concentration in serum.

• 생명과학회지
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• 제8권5호
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• pp.479-485
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• 1998

Xenopus 수정란의 동물극분리편에 IGF-1(Insulin-like Growth Factor-1)을 고농도로 처리해 주었을 때의 기관유도효과를 실험하였다. Activin A는 동물극 분리배양조직으로부터 다양한 기관을 분화시키며 이러한 효과는 처리 시간과 농도에 의존한다. 본 연구에서는 activin A 뿐만 아니라 IGF-1을 복합처리하여 특정 기관의 분화양상을 관찰하였다. Activin A는 100ng/ml 의 농도로, IGF-1은 0-500 ng/ml의 범위로 조합 처리하였다. 분리편은 정상배가 st. 43에 이를 때까지 배양하였으며, 이때 activin A를 100ng/ml의 고농도로 처리하면 조직이 파괴되는 것이 일반적이다. 그리고 신관의 발생에 대해서는 activin A와 retinoic acid의 복합처리가 매우 효과적인 방법으로 알려져 있으나, IGF-1의 첨가에 의해 신관을 비롯한 다른 조직들이 분화되었다. 또한, 눈의 분화는 activin A 1-100ng/m1와 IGF-1 500ng/ml의 농도범위에서 일어났다. Activin A의 저농도 (1ng/ml)처리에서는 혈구양세포가 분화하고 배양조직은 풍선처럼 부풀게되나 IGF-1의 첨가로 눈이 발생하게 되어 activin A상의 눈의 발생농도범위가 확대되었다.

• Asian-Australasian Journal of Animal Sciences
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• 제20권1호
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• pp.119-123
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• 2007

The objectives of this study were to characterize the changes occurring in the levels of insulin-like growth factors (IGF-I and IGF-II) in bovine milk during a one-year lactation period, and to determine the parameters affecting IGF content in bovine milk. Milk was collected individually from lactating Holstein cows (n=70), and IGF-I and -II levels were determined via radioimmunoassay, using 125I after acid-ethanol treatment. The proximate compositions of the milk samples were determined using a near-infrared milk analyzer. The data were analyzed by the GLM and CORR procedures using SAS software to determine significant differences (p<0.05) occurring within groups (dairy farms, lactation periods, season, and parity). We noted an approximately six-fold reduction in the IGF-I concentration (from 2,462.7 to 353.0 ng/ml) and a three-fold drop in the IGF-II concentration (from 929.1 to 365.7 ng/ml) in the bovine colostrum, between 6 h after parturition and 18 h after parturition. IGF-I and -II content, measured at the early, middle, and late stages of lactation did not change significantly throughout the entirety of the lactation period. Interestingly, parity did not significantly affect IGF-I content, but did significantly affect IGF-II content between the primiparous and multiparous cows. We also found there were no significant relationships between IGF-I and total protein content or somatic cell counts (p<0.05).