• Development and Reproduction
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• v.3 no.1
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• pp.69-74
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• 1999

Insulin-like growth factors (IGF-1 and IGF-2) play an important regulatory role in premplantation embryonic development. To study the role of IGF-1 during premplantation embryonic development in mouse, the presence of mRNA transcripts for IGF-1 and IGF-lR in the oocytes and preimplantation embryos was examined. In this study, the transcripts of IGF-1 was detected in oocytes using primers for IGF-1. The PCR products were identified by Msp I restriction enzyme digest. We revealed that the transcripts of IGF-1 and IGF-1R were presented in the oocytes and preimplantation embryos. The highest mRNA levels in GV stage oocytes were decreased at 4- or 8-cell stage and then reincreased upto blastocyst. The presence of IGF-1 and IGF-lR in GV-oocytes suggests that the transcripts in the early stage embryos were derived from maternal genome. Additionally, the presence of IGF-1 and IGF-lR in the oocytes and preimplantation embryos suggests that IGF-1 plays an autocrine role during preimplantation embryonic development through IGF-lR as a signalling pathway.

• Journal of Animal Science and Technology
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• v.50 no.5
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• pp.649-656
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• 2008

The current study was undertaken to investigate the mechanism of action of insulin-like growth factors (IGFs) on proliferation and differentiation of pig preadipocytes. The preadipocytes were isolated from the backfat of new-born female pigs and cultured in serum-deprived medium in the presence and absence of recombinant native IGFs or recombinant mutant IGFs that have reduced affinity for binding to both type-1 IGF receptors and insulin receptors. Fifty ng/ml of either IGF-I, [Leu60]IGF-I, IGF-Ⅱ or [Leu27]IGF-Ⅱ were included in the media in which preadipocytes were cultured for 4 days. IGF-I, [Leu60]IGF-I, IGF-Ⅱ and [Leu27]IGF-Ⅱ stimulated proliferation of pig preadipocytes by 39%, 8%, 25% and 2% respectively, as measured by increased numbers of cells. This indicates that both IGF-I and -II promote replication of pig preadipocytes by actions mediated either by type-1 IGF receptor or insulin receptor. IGF-I, [Leu60]IGF-I, IGF-Ⅱ and [Leu27]IGF-Ⅱ stimulated differentiation of pig preadipocytes by 50%, 17%, 37% and 30%, respectively, measured as glycerolphosphate dehydrogenase activity. Reducing the affinity of IGF-I for type-1 IGF receptors or insulin receptors significantly reduced the differentiation response. However, the differentiation response to [Leu27]IGF-II was not significantly different from the response to IGF-II. This shows that IGF-I and IGF-Ⅱ promote cell differentiation by different receptor-mediated mechanisms. IGF-II promotes differentiation of pig preadipocytes by actions that do not involve either type-1 IGF receptors or insulin receptors. These actions therefore appear to be mediated by binding of IGF-II to type-2 IGF receptors(also known as cation-independendent mannose-6-phosphate receptor[CIM6P/IGF2 receptor]). This is the first study to find evidence that IGF-II promotes differentiation of preadipocytes from any animal species by actions mediated by CIM6P/IGF2 receptors. In summary, this study shows that IGF-I and IGF-Ⅱ promote differentiation of pig preadipocytes by mechanisms that involve different cellular receptors.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.1
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• pp.221-225
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• 2015

As metformin can inhibit endometrial carcinoma (EC) cell growth and the insulin growth factor (IGF) system is active in EC, the question of whether it can regulate endometrial carcinoma cell secretion of IGF-1 or expression of IGF-1 receptor (IGF-1R) is of interest. In this study, serum IGF-1 levels in EC patients were found to be comparable with that in the non EC patients (p>0.05). However, the IGF-1 level in the medium of cultured cells after treatment with metformin was decreased (p<0.05). IGF-1R was highly expressed in human endometrial carcinoma paraffin sections, but IGF-1R and phosphor-protein kinase B/protein kinase B (p-Akt/Akt) expression was down-regulated after metformin treatment (p<0.05). In summary, metformin can reduce the secretion of IGF-1 by Ishikawa and JEC EC cell lines and their expression of IGF-1R to deactivate downstream signaling involving the PI-3K/Akt pathway to inhibit endometrial carcinoma cell growth.

• Korean Journal of Animal Reproduction
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• v.27 no.1
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• pp.1-7
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• 2003

Transgenic rabbits were produced by DNA microinjection using growth hormone receptor (GHR) and IGF-1 receptor (IGF-1R) genes fused to metallothionein(MT) promoter. The overall efficiencies for production of transgenic rabbits were 3.2% and 3.1% for GHR and IGF-lR genes, respectively. Founder rabbits transmitted transgenes to their progenies through medelian fashion. Growth rate of GHR and IGF-lR transgenic rabbits was significantly faster than that of non-transgenic rabbits. Transgenic rabbits grew large. (25% and 15% increase in body weight of GHR and IGF-lR transgenic rabbits, respectively) than non-transgenic rabbits and organ weight of transgenic rabbits increased, suggesting that GHR and IGF-1R genes affects growth rates in transgenic rabbits.

• Journal of Embryo Transfer
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• v.13 no.3
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• pp.245-249
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• 1998

The purpose of this study was to evaluate the effects of growth factors such as epidermal growth factor (EGF) and insulin-like growth factor-1 (IGF-1) on maturation of bovine follicular oocytes in vitro. Oocytes were recovered from the ovaries of slaughtered Hanwoos. The oocytes were matured in TCM 199 at 39$^{\circ}C$, 5% $CO_2$ in air. Growth factors were added to maturation medium as follows: control (no serum), EGF (10ng/m1, 50ng/ml or 100ng/m1), IGF-1 (100ng/m1) and EGF (50ng/ml) + IGF-1 (100ng/m1). The oocytes were placed onto a slide and stained with aceto-orcein dye. Nuclear maturation was evaluated and classified as germinal vesicle breakdown (GVBD), metaphase-I (MI) or metaphase-ll(Mll). Maturation rates were 37.9% (control), 45.8% (EGF, 10ng/m1), 55.8% (EGF, 50ng/ml), 44.4% (EGF, 100ng/m1), 46.7% (IGF-1, 100ng/m1) and 67.0% (IGF-1+EGF). The highest group developed to Mll stage was IGF-1+EGF treatment group (p<0.05). Therefore, nuclear maturation of bovine oocytes were affected by both of growth factors, and it seems to have a mutual activity between them.

• Korean Journal of Veterinary Research
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• v.46 no.4
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• pp.315-322
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• 2006

Ethanol abuse is associated with liver injury, neurotoxicity, modulation of immune responses, and increased risk for cancer, whereas moderate ethanol consumption exerts protective effects against liver injury. However, the underlying signal transduction mechanisms of insulin-like growth factors (IGFs) which play an important regulatory role in various metabolism mechanisms are not well understood. We investigated the effects of ethanol-induced p42/44 activity on IGF-I secretion, IGF-I receptor and IGFBP-1 secretion using radioimmunoassay and western blotting in primary cultured rat hepatocytes. The p42/44 activity, IGF-I secretion and IGF-I receptor activity significantly accelerated compared to control at 10 and 30 min after 200 mM ethanol treatment, but then it became suppressed at 180 min. In contrast, IGFBP-1 secretion was inhibited compared to control at 30 min after 200 mM ethanol treatment, but increased at 180 min. The IGF-I secretion, IGF-I receptor and p42/44 activity at 30 min after 200 mM ethanol treatment accelerated with increasing ethanol concentration but IGFBP-1 secretion inhibited (p<0.05). The increased IGF-I secretion, inhibited IGFBP-1 secretion and IGF-IR activity by ethanol-induced temporal p42/44 activity at 30 min after ethanol treatment was blocked by treatment with PD98059. Alcohol dehydrogenase (ADH) inhibitor, 4-methylpyramazole blocked the changes of IGF-I secretion, IGFBP-1 secretion, and IGF-IR activity by ethanol-induced p42/44 activity at 30 and 180 min. Taken together, these results suggest that ethanol is involved in the modulation of IGF-I and IGFBP-1 secretion and IGF-IR activity by p42/44 activity in primary cultured rat hepatocytes. In addition, changing of p42/44 activity by ethanol was caused with ADH.

• Tuberculosis and Respiratory Diseases
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• v.63 no.1
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• pp.42-51
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• 2007

Background: TRAIL is a cytokine that selectively induces apoptosis in various cancer cell lines. Gefitinib is new targeted drug applied in lung cancer that selectively inhibits EGFR tyrosine kinase. However, lung cancers have shown an initial or acquired resistance to these drugs. This study examined the effect of IGF-1R and its blockade on enhancing the sensitivity of lung cancer cell lines to TRAIL and gefitinib. Methods: Two lung cancer cell lines were used in this study. NCI H460 is very sensitive to TRAIL and gefitinib. On the other hand, A549 shows moderate resistance to TRAIL and gefitinib. The IGF-1R blockade was performed using adenoviruses expressing the dominant negative IGF-1R and shRNA to IGF-1R and AG1024 (IGF-1R tyrosine kinase inhibitor). Results: The adenovirus expressing dominant negative IGF-1R(950st) induced the increased expression of defective IGF-1R on the lung cancer cell surface, and the adenovirus-shIGF-1R effectively decreased the level of IGF-1R expression on cell surface. The genetic blockade of IGF-1R by the adenovirus-dnIGF-1R and AG1024 increased the sensitivity of A549 cells to TRAIL. The reduction of IGF-1R by transduction with ad-shIGF-1R also increased the sensitivity of the A549 cells to gefitinib. Conclusion: The blockade of IGF-1R through various mechanisms increased the sensitivity of the lung cancer cell line that was resistant to TRAIL and gefitinib. However, further studies using other cell lines showing acquired resistance as well as in vivo animal experiments will be needed.

• Food Science of Animal Resources
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• v.24 no.2
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• pp.171-175
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• 2004

Insulin-like growth factor-I (IGF-I) rich fraction, which was obtained molecules ranged between 30 kDa and 1 kDa, was fractionated by ultrafiltration from bovine colostral whey with 30 kDa and 1 kDa membrane. IGF-I included in fractionated IGF-I rich fraction was confirmed by SDS-PAGE and western blotting and then the quantity of IGF-I was measured by ELISA. IGF-I concentration in IGF-I rich fraction was 10ng/mg protein. Effect of IGF-I rich fraction on in vitro proliferation of several cells was tested. IEC-6 cell proliferation rate was increased 60％. 53％, 30％, and 20％ at l0ng, 1ng, 0.1ng and IGF-I of IGF-I, respectively, compared to control group which was not supplemented by IGF-I rich fraction. IGF-I rich fraction stimulated in vitro proliferation of IEC-6 cell in a dose dependent manner by increasing cell number. Detroit 551 cell proliferation was enhanced 56％ and 26％ at 10ng and 1ng level of IGF-I, respectively, compared to control group. EL-4 cell and L6 cell proliferation was increased 53％ and 46％ at 10ng of IGF-I, respectively, compared to control group.

• Clinical and Experimental Pediatrics
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• v.52 no.2
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• pp.176-180
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• 2009

Purpose : The objective of this study was to establish the serum IGF-1 level in newborn infants, and investigate its association with growth and diseases. Methods : In a retrospective study, serum IGF-1 levels were measured for newborn infants admitted to NICU at Kyungpook University Hospital from March 2007 to July 2007. Birth data, disease history, and hospital course were obtained from medical records. Results : Of 52 blood samples obtained at birth, serum IGF-l levels in 30 preterm infants ($31.6{\pm}27.3$ ng/mL) were lower than in 22 full-term infants ($53.4{\pm}40.0$ ng/mL; P<0.05). In sick full-term infants, serum IGF-1 levels ($46.0{\pm}40.2$ ng/mL) were lower than in healthy full-term infants ($64.1{\pm}39.5$ ng/mL; P<0.05). In preterm infants, there were no differences in IGF-1 levels between healthy ($33.2{\pm}23.3$ ng/mL) and sick infants ($30.6{\pm}30.4$ ng/mL); however, IGF-1 levels in both sick and healthy preterm infants were lower than in healthy full-term infants. Among infants admitted after 8 days of life, serum IGF-1 levels were higher in infants who gained weight ($70.8{\pm}36.2$ ng/mL) than in infants who lost weight ($13.3{\pm}19.9$ ng/mL; P<0.01); however IGF-1 levels showed no difference between gender or method of delivery. Conclusion : The study showed lower IGF-l levels in preterm infants than in full-term infants. Additionally, the IGF-l level in infants with weight loss was lower than in infants with weight gain. These results indicate that serum IGF-1 is associated with gestational age and postnatal growth.

• Reproductive and Developmental Biology
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• v.30 no.2
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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.