• Journal of Animal Science and Technology
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• v.50 no.2
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• pp.177-184
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• 2008

Acid-labile subunit(ALS) is a 85-kDa glycosylated plasma protein which forms a 150-kDa ternary complex with 7.5-kDa insulin-like growth factor(IGF) and 40~45-kDa IGF-binding protein-3. In a previous study, the present authors prepared a porcine ALS(pALS) expression construct by inserting a pALS coding sequence into a plasmid vector following synthesis of the sequence by reverse transcription-polymerase chain reaction(RT-PCR). The expression construct, however, was subsequently found to have a mis-sense mutation at two bases of the pALS coding sequence which is presumed to have occurred through a PCR error. In the present study, the correct coding sequence was synthesized by the site-directed mutagenesis and inserted into the pET-28a(+) plasmid expression vector containing the His-tag sequence flanking the last codon of the insert DNA. After induction of the expression construct in E. coli BL21(DE3) cells, the resulting presumptive recombinant peptide was purified by the Ni-affinity chromatography. Upon SDS- PAGE, the affinity-purified peptide was resolved as a single band at a 66-kDa position which is consistent with the expected molecular mass of the presumptive recombinant pALS. Collectively, results indicate that a recombinant pALS peptide was successfully expressed and purified in the present study.

• BMB Reports
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• v.48 no.9
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• pp.501-506
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• 2015

Based on the potential beneficial effects of growth hormone releasing peptide (GHRP)-6 on muscle functions, a newly synthesized GHRP-6-biotin conjugate was tested on cultured myoblast cells. Increased expression of myogenic marker proteins was observed in GHRP-6-biotin conjugate-treated cells. Additionally, increased expression levels of insulin-like growth factor-1 and collagen type I were observed. Furthermore, GHRP-6-biotin conjugate-treated cells showed increased metabolic activity, as indicated by increased concentrations of energy metabolites, such as ATP and lactate, and increased enzymatic activity of lactate dehydrogenase and creatine kinase. Finally, binding protein analysis suggested few candidate proteins, including desmin, actin, and zinc finger protein 691 as potential targets for GHRP6-biotin conjugate action. These results suggest that the newly synthesized GHRP-6-biotin conjugate has myogenic stimulating activity through, at least in part, by stimulating collagen type I synthesis and several key proteins. Practical applications of the GHRP-6-biotin conjugate could include improving muscle condition. [BMB Reports 2015; 48(9): 501-506]

• BMB Reports
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• v.52 no.6
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• pp.385-390
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• 2019

Leptin, an adipokine regulating energy metabolism, appears to be associated with breast cancer progression. Insulin-like growth factor-1 (IGF-1) mediates the pathogenesis of breast cancer. The regulation of IGF-1 expression by leptin in breast cancer cells is unclear. Here, we found that leptin upregulates IGF-1 expression at the transcriptional level in breast cancer cells. Activating protein-1 (AP-1)-binding element within the proximal region of IGF-1 was necessary for leptin-induced IGF-1 promoter activation. Forced expression of AP-1 components, c-FOS or c-JUN, enhanced leptin-induced IGF-1 expression, while knockdown of c-FOS or c-JUN abrogated leptin responsiveness. All three MAPKs (ERK1/2, JNK1/2, and p38 MAPK) mediated leptin-induced IGF-1 expression. These results suggest that leptin contributes to breast cancer progression through the transcriptional upregulation of leptin via the MAPK pathway.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.8
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• pp.1180-1185
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• 2009

Two experiments were carried out to study the effects of dietary energy level on nutrient digestion, nitrogen (N) utilization, growth performance, insulin-like growth factor-I (IGF-I), and insulin-like growth factor binding protein-3 (IGFBP-3) in plasma, liver and longissimus dorsi muscle in growing-finishing pigs. In experiment 1 (Exp 1), 15 castrated male pigs (Duroc${\times}$Landrace${\times}$Large White) (Body weight, BW, 55.6${\pm}$1.8 kg) were divided into three groups and fed rations containing 13.33, 14.87 and 17.35 MJ digestible energy (DE)/kg as treatments I, II and III, respectively, using soybean oil as an energy source. The experiment lasted 8 days and faecal and urinary samples were collected during the last 3 days. The results showed that the digestibility of dry matter (DM), energy and N was increased from treatments I to III (p<0.01). N-retention and N-retention rate were not influenced by dietary DE level (p>0.05). In experiment 2 (Exp 2), 36 female pigs (Duroc${\times}$Landrace${\times}$Large White) (BW 41.5${\pm}$3.8 kg) were divided into three groups. The pigs were fed with the same three rations used in Exp 1 for 60 days. At the end of Exp 2, eight pigs were selected from each group for blood sampling and 4 pigs for slaughter trial. The results indicated that average daily feed intake (ADFI) and N-intake were significantly decreased (p<0.01), and DE intake (p<0.01) and average daily gain (ADG) (p<0.05) were increased. IGF-I and IGFBP-3 in plasma were increased (p<0.05). No significant differences in IGF-I and IGFBP-3 in liver and longissimus dorsi muscle were found between different treatments. It was concluded that higher dietary DE level improved nutrient digestibility, ADG and feed/gain ratio when soybean oil was used as an energy source in the ration of growing-finishing pigs. No significant differences were found in Nretention and IGF-I and IGFBP-3 in liver and longissimus dorsi muscle between different treatments.

• Fisheries and Aquatic Sciences
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• v.22 no.9
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• pp.19.1-19.10
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• 2019

We investigated the insulin-like growth factor 1 (IGF-1)/AKT signaling pathway involved in muscle formation, growth, and movement in the adductor muscle of triploid Pacific oyster, Crassostrea gigas. Large and small triploid oysters (LTs and STs) cultured under identical conditions were screened, and the signaling pathways of individuals with superior growth were compared and analyzed. mRNA and protein expression levels of actin, troponin, tropomyosin, and myosin, proteins important in muscle formation, were higher in LTs compared with STs. Expression levels of IGF-1, IGF binding protein (IGFBP), and IGFBP complex acid-labile subunit were also higher in LTs compared with STs. Phosphorylation of the IGF receptor as well as that of AKT was high in LTs. In addition, the expression of phosphomammalian target of rapamycin and phospho-glycogen synthase kinase $3{\beta}$ was increased and the expression of Forkhead box O3 was decreased in LTs. Therefore, we suggested that the IGF-1/AKT signaling pathway affects the formation, growth, and movement of the adductor muscle in triploid oysters.

• Clinical and Experimental Pediatrics
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• v.48 no.3
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• pp.298-305
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• 2005

Purpose : We performed this study to evaluate the mean serum levels of insulin-like growth factor (IGF)-I, insulin-like growth factor binding protein(IGFBP)-2 and IGFBP-3 in healthy Korean children according to age and sex. Methods : Ninety two healthy children, consisting of 42 boys and 50 girls, were classified into five groups according to age : neonate; infancy; early childhood; late childhood; and adolescence. We measured serum levels of IGF-I, IGFBP-2 and IGFBP-3 by enzyme-linked immunosorbent assay(ELISA) and analysed the serum levels according to sex and age group. Results : For boys, the mean serum levels of IGF-I(ng/mL) in neonate, infancy, early childhood, late childhood and adolescence were $41.1{\pm}3.6$, $70.9{\pm}33.7$, $103.5{\pm}97.2$, $89.8{\pm}46.5$ and $51.4{\pm}27.8$, respectively. Those of IGFBP-2(ng/mL) were $8.2{\pm}3.4$, $5.8{\pm}0.4$, $9.3{\pm}4.0$, $9.5{\pm}1.1$ and $7.0{\pm}0.5$, respectively. Those of IGFBP-3(ng/mL) were $559.2{\pm}215.2$, $1,333.3{\pm}692.5$, $2,254.6{\pm}1,513.8$, $2,447.1{\pm}1,464.2$, $1,533.6{\pm}807.4$, respectively. For girls, the mean serum levels of IGF-I(ng/mL) according to five age groups were $53.3{\pm}9.5$, $99.3{\pm}45.8$, $69.6{\pm}51.1$, $106.2{\pm}67.0$ and $145.1{\pm}127.8$, respectively. Those of IGFBP-2 (ng/mL) were $9.1{\pm}7.4$, $5.3{\pm}0.9$, $6.9{\pm}2.0$, $10.5{\pm}3.0$ and $7.9{\pm}1.3$, respectively. Those of IGFBP-3(ng/mL) were $858.2{\pm}433.4$, $1,834.8{\pm}851.3$, $1,404.3{\pm}570.2$, $2,203.5{\pm}899.4$ and $2,029.3{\pm}1,316.7$, respectively. There were significant positive correlations observed between IGF-I and IGFBP-3 levels(r=0.589, P=0.000). Conclusion : IGF-I and IGFBP-3 levels increased as children get older. The peak level of IGFBP-3 was observed in late childhood for both boys and girls, suggesting a current trend of children reaching peak growth velocity before adolescence. The IGFBP-2 level was higher in neonates compare to infancy, suggesting that IGFBP-2 is an important substance for fetal growth.

• Biomedical Science Letters
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• v.10 no.3
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• pp.203-210
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• 2004

It has been reported that glomerulosclerosis mediated by the dysfunction of mesangial cells and insulin-like growth factors (IGFs) are associated with the development of diabetic nephropathy. However, it is not yet known the effect of high glucose on IGF-I, -II secretion, IGF-I receptor, and IGFBPs expression in the mesangial cells. Thus, this study was conducted to examine the effect of high glucose on IGF system and its involvement of protein kinase C (PKC) and oxidative stress in mesangial cells. In this study, high glucose (25 mM) increased IGF-I and IGF-II secretion and mRNA expression (P<0.05), which was blocked by PKC inhibitor (staurosporine, 10/sup -8/ M) and antioxidant (N-acetyl cystein, 10/sup -5/ M). High glucose decreased IGFBP-1 and -2 expression but increased IGFBP-5 expression. These alteration of IGFBPs by high glucose was also prevented by staurosporine and NAC, suggesting the role of PKC and oxidative stress. Indeed, high glucose increased PKC activity. Furthermore, high glucose-induced increase of lipid peroxide (LPO) formation was blocked by PKC inhibitors. In conclusion, high glucose alters IGF system via PKC-oxidative pathways in mesangial cells.

• Molecules and Cells
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• v.42 no.4
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• pp.321-332
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• 2019

The brain is the most common metastatic site of lung adenocarcinoma; however, the mechanism of this selective metastasis remains unclear. We aimed to verify the hypothesis that exposure of tumor cells to the brain microenvironment leads to changes in their gene expression, which promotes their oriented transfer to the brain. A549 and H1299 lung adenocarcinoma cells were exposed to human astrocyte-conditioned medium to simulate the brain microenvironment. Microarray analysis was used to identify differentially expressed genes, which were confirmed by quantitative real-time PCR and western blotting. Knockdown experiments using microRNAs and the overexpression of genes by cell transfection were performed in addition to migration and invasion assays. In vitro findings were confirmed in clinical specimens using immunohistochemistry. We found and confirmed a significant increase in insulin-like growth factor binding protein-3 (IGFBP3) levels. Our results also showed that the up-regulation of IGFBP3 promoted A549 cell epithelial-mesenchymal transition, migration, and invasion, while the knockdown of IGFBP3 resulted in decreased cell motility. We also found that Transforming growth factor-${\beta}$ (TGF-${\beta}$)/Mothers against decapentaplegic homolog 4 (Smad4)-induced epithelial-mesenchymal transition was likely IGFBP3-dependent in A549 cells. Finally, expression of IGFBP3 was significantly elevated in pulmonary cancer tissues and intracranial metastatic tissues. Our data indicate that up-regulation of IGFBP3 might mediate brain metastasis in lung adenocarcinoma, which makes it a potential therapeutic target.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.5
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• pp.606-612
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• 2012

Insulin-like growth factor-binding protein-5 (IGFBP-5) is one of the six members of IGFBP family, important for cell growth, apoptosis and other IGF-stimulated signaling pathways. In order to explore the significance of IGFBP-5 in cells of the Inner Mongolian Cashmere goat (Capra hircus), IGFBP-5 gene complementary DNA (cDNA) was amplified by reverse transcription polymerase chain reaction (RT-PCR) from the animal's fetal fibroblasts and tissue-specific expression analysis was performed by semi-quantitative RT-PCR. The gene is 816 base pairs (bp) in length and includes the complete open reading frame, encoding 271 amino acids (GenBank accession number JF720883). The full cDNA nucleotide sequence has a 99% identity with sheep, 98% with cattle and 95% with human. The amino acids sequence shares identity with 99%, 99% and 99%, respectively. The bioinformatics analysis showed that IGFBP-5 has an insulin growth factor-binding protein homologues (IB) domain and a thyroglobulin type-1 (TY) domain, four protein kinase C phosphorylation sites, five casein kinase II phosphorylation sites, three prenyl group binding sites (CaaX box). The IGFBP-5 gene was expressed in all the tested tissues including testis, brain, liver, lung, mammary gland, spleen, and kidney, suggesting that IGFBP-5 plays an important role in goat cells.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.3
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• pp.307-315
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• 2001

Litter size has been one of the important economic traits in porcine reproduction. The insulin-like growth factor (IGF) system has been shown to mediate actions of the steroid hormone or to synergize with other endocrine factors so that it consequently plays roles in reproductive processes, including ovulation, implantation, maintenance of pregnancy, and fetal development. However, the effect of the serum IGF system on porcine litter size has not been deeply studied. Therefore, this study was conducted to relate serum IFG-II concentration and IGF binding protein-3 (IGFBP-3) expression with porcine litter size. Moreover, the possible association of those with estrogen receptor (ER) as a candidate gene for litter size was investigated. Swine were separated into two groups showing high and low litter sizes, and sera were collected from sows in the estrous cycle to postnatal growth of their female progeny. Serum IFG-II concentration was measured by radioimmunoassay and IGFBP-3 expression was detected by Western ligand blotting. During the estrous cycle, IGFBP-3 expression in both groups decreased moderately from metestrus to estrus, but IFG-II concentration showed a reverse pattern. Also, IFG-II concentration and IGFBP-3 expression decreased gradually as pregnancy proceeded. Unlike IGFBP-3, IFG-II decreased moderately as newborn pigs grew. Significant differences in serum IFG-II amount between the two groups were detected at 60 (p<0.01), 75, 90, and 105 d (p<0.05) of pregnancy and at 60 (p<0.01), 45, and 105 d (p<0.05) of postnatal growth. Furthermore, based on ER genotypes, a high litter size group with genotypes AB and BB showed lower IFG-II concentration than a low litter size group with a genotype AA during pregnancy. Taken together, the results indicate that the serum IFG-II and IGFBP-3 are correlated with the litter size in pigs.