• 생명과학회지
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• 제25권10호
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• pp.1098-1102
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• 2015

본 연구에서는 C2C12 근육 세포의 분화 과정에 있어 IGF-I이 지방산의 수송을 담당하는 FABPpm mRNA 및 단백질 발현에 어떠한 영향을 미치는지에 대해 알아보았다. 그 결과 근육세포의 분화에 있어 FABPpm의 단백질과 mRNA 발현이 IGF-I에 의해 유의하게 조절되었음을 알 수 있었다. 이는 기존의 여러 연구의 결과인 IGF-I이 골격근에서 근육 관련 유전자들의 발현을 조절하여 근부피 유지 및 증대에 중심적인 역할 것뿐만 아니라, 지방산의 수송을 담당하는 FABPpm의 발현에도 영향을 미친다는 사실을 밝혔다는 것에 의의가 있다고 생각된다. 향후 골격근에서 IGF-I에 의한 FABPpm 발현 조절에 있어, 세포 내부에서의 신호전달 경로 및 상호작용 인자들에 관한 연구를 통해 지방 대사를 조절하는 기전에 관한 연구가 필요할 것으로 사료된다.

• Asian-Australasian Journal of Animal Sciences
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• 제18권11호
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• pp.1542-1547
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• 2005

The Melanocortin-4 Receptor (MC4R) and Insulin-like Growth Factor 2 (IGF2) are two important candidate genes related to fat deposition and carcass traits. MC4R was found on study on human obesity and then was studied as candidate gene affecting food intake and fat deposition traits in mice and pigs. Insulin-like Growth Factor 2 (IGF2) gene plays an important role on tumor cell proliferation and muscle growth. It also affects fat traits and live weight in pigs. In this paper, MC4R and IGF2 were studied as two candidate genes associated with important economic traits such as fat deposition and carcass traits in five different pig populations. Taq I-PCR-RFLP and Bcn I-PCR-RFLP were respectively used to detect the polymorphism of genotypes of MC4R and IGF2 genes. Different MC4R genotype frequencies were observed in four populations. IGF2 genotype frequencies were also different in two populations. The results of association analysis show both MC4R and IGF2 genes were significantly associated with fat deposition and carcass traits in about 300 pigs. This work will add new evidence of MC4R and IGF2 affecting fat deposition and carcass traits in pigs and show that two genes can be used as important candidate genes for marker assistant selection (MAS) of growth and lean meat percentage in pigs.

• 생명과학회지
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• 제27권8호
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• pp.879-887
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• 2017

히스톤 탈 아세틸 효소(HDAC)와 인슐린유사성장인자(IGF-I)는 근육 관련 유전자들의 활성 및 발현을 조절하여 골격근의 성장 및 발달을 조절하지만 이들이 근신경계 발달 및 대사 기능에 중요한 역할을 담당하는 뇌신경성장인자(BDNF)의 발현에 미치는 영향에 관한 연구는 거의 이루어지지 않았다. 따라서 본 연구에서는 IGF-I과 HDAC의 억제제인 SAHA가 C2C12 골격근 세포에서 BDNF 발현에 미치는 영향을 알아보고자 하였다. 그 결과 IGF-I은 농도와 시간 의존적으로 BDNF의 mRNA 및 단백질 발현을 감소시켰지만 HDAC을 억제하자 IGF-I에 의해 감소되었던 BDNF의 발현이 증가하는 경향을 관찰할 수 있었다. 따라서 IGF-I은 BDNF의 발현을 억제하며, HDAC의 억제는 IGF-I에 의한 BDNF의 발현 억제를 감소시킬 수 있다는 사실을 확인할 수 있었다.

• Asian-Australasian Journal of Animal Sciences
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• 제19권10호
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• pp.1508-1513
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• 2006

Myostatin (MSTN) and insulin-like growth factors (IGFs) are a known inhibitor and stimulators of proliferation and differentiation of muscle cells, respectively. The present study was performed to investigate the relationship of MSTN-induced growth inhibition to expression of the IGF system components and myogenin, a muscle cell-specific transcription factor, in rat L6 myoblasts. The L6 cells transfected with a green fluorescent protein-MSTN plasmid expression construct had a 47% less cell number than mock-transfected cells after 3-d serum-free culture, accompanied by delayed differentiation which was suggested by inhibited aggregation of cells. Moreover, cells transfected with the expression construct had decreased expression of IGF-II and myogenin genes, but not IGF-I or its receptor genes, as examined by reverse transcription-polymerase chain reaction. The reduced mitosis of the L6 cells transfected with the MSTN-expression construct increased following an addition of either IGF-I or IGF-II to the culture medium, but not to the level of mock-transfected cells. By contrast, myogenin gene expression in these cells increased after the addition of either IGF to the level of mock-transfected cells. Collectively, these results suggest that the inhibitory effect of MSTN on L6 cell proliferation and differentiation is likely to be partly mediated by serially suppressed expression of IGF-II and myogenin genes, not IGF-I gene.

• Asian-Australasian Journal of Animal Sciences
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• 제18권5호
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• pp.747-754
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• 2005

Nutritional regulation of gene expression associated with growth and feeding behavior in avian species can become an important technique to improve poultry production according to the supply of nutrients in the diet. Insulin-like growth factor-I (IGF-I) found in chickens has been characterized to be a 70 amino acid polypeptide and plays an important role in growth and metabolism. Although it is been well known that IGF-I is highly associated with embryonic development and post-hatching growth, changes in the distribution of IGF-I gene expression throughout early- to late-embryogenesis have not been studied so far. We revealed that the developmental pattern of IGF-I gene expression during embryogenesis differed among various tissues. No bands of IGF-I mRNA were detected in embryonic liver at 7 days of incubation, and thereafter the amount of hepatic IGF-I mRNA was increased from 14 to 20 days of incubation. In eyes, a peak in IGF-I mRNA levels occurred at mid-embryogenesis, but by contrast, IGF-I mRNA was barely detectable in the heart throughout all incubation periods. In the muscle, no significant difference in IGF-I gene expression was observed during different stages of embryogenesis. After hatching, hepatic IGF-I gene expression as well as plasma IGF-I concentration increases rapidly with age, reaches a peak before sexual maturity, and then declines. The IGF-I gene expression is very sensitive to changes in nutritional conditions. Food-restriction and fasting decreased hepatic IGF-I gene expression and refeeding restored IGF-I gene expression to the level of fed chickens. Dietary protein is also a very strong factor in changing hepatic IGF-I gene expression. Refeeding with dietary protein alone successfully restored hepatic IGF-I gene expression of fasted chickens to the level of fed controls. In most circumstances, IGF-I makes a complex with specific high-affinity IGF-binding proteins (IGFBPs). So far, four different IGFBPs have been identified in avian species and the major IGFBP in chicken plasma has been reported to be IGFBP-2. We studied the relationship between nutritional status and IGFBP-2 gene expression in various tissues of young chickens. In the liver of fed chickens, almost no IGFBP-2 mRNA was detected. However, fasting markedly increased hepatic IGFBP-2 gene expression, and the level was reduced after refeeding. In the gizzard of well-fed young chickens, IGFBP-2 gene expression was detected and fasting significantly elevated gizzard IGFBP-2 mRNA levels to about double that of fed controls. After refeeding, gizzard IGFBP-2 gene expression decreased similar to hepatic IGFBP-2 gene expression. In the brain, IGFBP-2 mRNA was observed in fed chickens and had significantly decreased by fasting. In the kidney, IGFBP-2 gene expression was observed but not influenced by fasting and refeeding. Recently, we have demonstrated in vivo that gizzard and hepatic IGFBP-2 gene expression in fasted chickens was rapidly reduced by intravenous administration of insulin, as indicated that in young chickens the reduction in gizzard and hepatic IGFBP-2 gene expression in vivo stimulated by malnutrition may be, in part, regulated by means of the increase in plasma insulin concentration via an insulin-response element. The influence of dietary protein source (isolated soybean protein vs. casein) and the supplementation of essential amino acids on gizzard IGFBP-2 gene expression was examined. In both soybean protein and casein diet groups, the deficiency of essential amino acids stimulated chickens to increase gizzard IGFBP-2 gene expression. Although amino acid supplementation of a soybean protein diet significantly decreased gizzard IGFBP-2 mRNA levels, a similar reduction was not observed in chickens fed a casein diet supplemented with amino acids. This overview of nutritional regulation of IGF-I and IGFBP-2 gene expression in young chickens would serve for the establishment of the supply of nutrients to diets to improve poultry production.

• Asian-Australasian Journal of Animal Sciences
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• 제25권8호
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• pp.1055-1062
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• 2012

Two SNPs, i.e. L127V and T172M, of bovine growth hormone (GH) causing the presence of GH gene haplotypes A, B, and C was previously shown to alter intramuscular fatty acid (FA) composition in Japanese Black (JB) heifers. To determine the SNP effect on somatotropic hormone concentration and lipogenesis, we measured plasma GH, insulin, and insulin-like growth factor-1 (IGF-1) concentrations. We also measured mRNA levels of fatty acid synthase (FASN), stearoyl-coA desaturase (SCD), and sterol regulatory element binding proteins-1 (SREBP-1) and FA composition in diaphragm tissues. Heifers with genotype CC had the lowest plasma insulin concentration and FASN and SCD mRNA levels among genotypes. FASN mRNA levels in haplotype A tended to positively correlate with saturated FA (SFA) content and negatively correlated with C18:2 and unsaturated FA (USFA) contents. SCD mRNA levels in haplotype A positively correlated with monounsaturated FA (MUFA) contents and negatively correlated with C18:0 content. They also tended to positively correlate with C16:1, C18:1, and USFA contents and USFA/SFA ratio and negatively correlate with SFA content. Taken together, GH gene polymorphism affects the lipogenic genes expression levels and their relationships with fatty acid compositions in diaphragm tissues of JB heifers at 31 months of age.

• Journal of Animal Science and Technology
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• 제57권9호
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• pp.31.1-31.11
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• 2015

Background: This study was conducted to investigate the potential association of variation in the insulin-like growth factor binding protein 2 (IGFBP2) gene with growth, carcass and meat quality traits in pigs. IGFBP2 is a member of the insulin-like growth factor binding protein family that is involved in regulating growth, and it maps to a region of pig chromosome 15 containing significant quantitative trait loci that affect economically important trait phenotypes. Results: An IGFBP2 polymorphism was identified in the Michigan State University (MSU) Duroc ${\times}$ Pietrain $F_2$ resource population (n = 408), and pigs were genotyped by MspI PCR-RFLP. Subsequently, a Duroc pig population from the National Swine Registry, USA, (n = 326) was genotyped using an Illumina Golden Gate assay. The IGFBP2 genotypic frequencies among the MSU resource population pigs were 3.43, 47.06 and 49.51 % for the AA, AB and BB genotypes, respectively. The genotypic frequencies for the Duroc pigs were 9.82, 47.85, and 42.33 % for the AA, AB and BB genotypes, respectively. Genotype effects (P < 0.05) were found in the MSU resource population for backfat thickness at $10^{th}$ rib and last rib as determined by ultrasound at 10, 13, 16 and 19 weeks of age, ADG from 10 to 22 weeks of age, and age to reach 105 kg. A genotype effect (P < 0.05) was also found for off test Longissimus muscle area in the Duroc population. Significant effects of IGFBP2 genotype (P < 0.05) were found for drip loss, 24 h postmortem pH, pH decline from 45 min to 24 h postmortem, subjective color score, CIE $L^*$ and $b^*$, Warner-Bratzler shear force, and sensory panel scores for juiciness, tenderness, connective tissue and overall tenderness in MSU resource population pigs. Genotype effects (P < 0.05) were found for 45-min pH, CIE $L^*$ and color score in the Duroc population. Conclusions: Results of this study revealed associations of the IGFBP2 genotypes with growth, carcass and meat quality traits in pigs. The results indicate IGFBP2 as a potential candidate gene for growth rate, backfat thickness, loin muscle area and some pork quality traits.

• Clinical and Experimental Reproductive Medicine
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• 제23권3호
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• pp.247-268
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• 1996

여포와 난포의 성숙, 배란과 착상, 임신의 유지와 태아의 성장 발달, 분만 및 유선발육과 비유 등 일련의 생식현상에서 있어서 성선자극호르몬과 스테로이드 호르몬의 작용이 중추적인 역할을 한다는 사실은 오래 전부터 알려져왔다. 그러나 이러한 일련의 현상에 고전적인 호르몬 외에도 다수의 성장인자가 관여되고 있음이 최근의 연구 결과 밝혀지고 있다. 생식기관에서 성장인자들은 대부분 autocrine/paracrine mode로 작용하여, 성선자극호르몬과 스테로이드 호르몬의 작용을 매개하거나 이들 호르몬 등과 교호적인 작용(synergy)을 한다. 생식기관 내 insulin-like growth factor(IGF) system은 최근 가장 활발히 연구된 분야 중의 하나로 생식현상의 전반에 걸쳐 중요한 역할을 하고 있음이 밝혀졌다. 본 지면에서는 IGF system에 관한 개괄적인 정보를 소개하고 현재까지 보고된 intrauterine IGF system에 관한 연구를 요약하고자 한다. IGF family는 IGF-I과 IGF-II ligands, 두종류의 IGF receptors(수용체), 그리고 지금까지 발견된 6종류의 IGF-binding proteins(IGFBPs)로 이루어져 있다. IGF-I과 IGF-II는 proinsulin과 상동한 구조를 가진 peptide로서 포도당과 아미노산 운반을 자극하는 등 insulin과 유사한 작용을 한다. 이 외에도 IGFs는 세포분열촉진제(mitogens)로서 여러 형태의 세포에 걸쳐 세포증식을 자극하고, 세포의 분화(differentiation)과 세포기능의 발현에 관여한다. IGFs는 간과 주로 messenchymal cells에서 발현되어 endocrine mode는 물론 autocrine/paracrine mode로 거의 모든 조직에 작용한다. IGF 수용체는 두종류가 알려져 있는데 type I IGF receptor는 tyrosine kinase로서 IGF-I과 IGF-II에 공히 high-affinity를 나타내고, 상기한 대부분의 IGFs의 작용을 매개한다. Type II IGF receptor 혹은 IGF-II/mannose-6-phosphate receptor는 두개의 서로 다른 binding sites를 가지고 있는데 IGF-II binding site는 IGF-II에만 high-affinity를 나타낸다. Type II IGF receptor의 주요 역할은 IGF-II를 lysosomal targeting하여 ligand를 파괴하는데 있다. 체액 속의 IGFs는 대부분 IGFBP에 결합되어 있다. IGFBPs는 IGF의 저장/운반체 혹은 IGF 작용을 조절하는 역할을 하는 것으로 알려져 있으나 개개 IGFBP의 역할에 대해서는 지극히 제한된 정보만이 알려져 있다. IGFBPs의 IGF ligands에의 affinity는 IGF receptors의 IGFs에의 affinity보다 크기 때문에 대부분의 in vitro 상황 하에서 IGFBPs는 IGF 작용을 억제한다. IGFBP에 결합되어 있는 IGF가 어떤 기작에 의해 IGFBP로부터 분리되어 IGF receptor에 도달하는지는 알려지지 않고 있으나, 혈액과 조직액에 들어있는 불특정 IGFBP protease activity는 IGF의 방출과정에서 일역을 하는 것으로 믿어지고 있다. 최근 연구보고에 의하면 특정 in vitro 상황 하에서 IGFBP-1, -3, -5 등은 IGF와 무관한 작용도 있다는 증빙이 있어 IGF system의 또 다른 차원을 예고하고 있다. IGF family members의 mRNAs & proteins는 영장류, 설치류 및 가축의 자궁조직과 수태물(conceptus)에서 발현되어 자궁과 태아의 성장 발달에 중요한 역할을 한다. 자궁조직의 IGF system의 발현은 성선호르몬, 국소 생리조절인자 등에 의해 발현시기와 장소의 특이성이 결정되며, 발현된 IGFs와 IGFBPs는 autocrine/paracrine mode로 자궁조직에 작용하기도 하고, 자궁강에 분비되어 수태물의 성장 발달에 관여한다. 착상을 전후하여 수태물에서도 IGF system이 발현되는데 개개 IGF family member의 발현 시기는 모체로부터 유래된 mRNA의 유무, 수태물 자체의 genetic programming, 모체와의 상호작용 등에 의해 결정되고, IGFs의 작용 부위 역시 시간(생리적 상태)과 장소의 특이성이 있다. 이와같이 conceptus IGF system의 발현이 시간적, 공간적으로 조절되고있다는 사실은 IGFs가 수태물의 성장 발달에 일역을 한다는 가설을 간접적으로 지지해 준다. 자궁조직과 수태물에서 발현된 IGFs는 세포의 증식과 분화, 포도당과 아미노산의 운반과 단백질합성, placental lactogen과 prolactin 등과 같은 유선자극호르몬의 생성을 자극하고 스테로이드 호르몬의 합성에도 관여한다. 태아의 성장 발달에 있어서 IGFs의 역할은 embryo의 IGF-I, IGF-II, 혹은 IGF receptor gene을 homologous recombination technique에 의해 파괴(gene targeting)하여을 때의 결과로써 입증되었다. 생쥐의 IGF and/or IGF-II gene 혹은 IGF receptor gene을 파괴했을 때 출생 전후 모두 성장 발달이 지연되며 출생시 무게는 정상치의 30-60% 수준에 머물고, 특히 type I IGF receptor gene 혹은 IGF-I과 IGF-II genes를 모두 파괴했을 경우에는 출생 후 곧 치사한다. 자궁 내의 IGFBPs는 IGF ligands를 자궁 내에 제한시키거나 IGFs의 receptor binding을 억제하는 negative regulators 역할을 하는 것으로 믿어지고 있다. 그러나 영장류의 자궁에서 IGFBP-I과 같은 특정 IGFBP는 IGFs보다 월등히 많은 양이 발현 분비되고 있는 것으로 추산되고 있으며, 또한 이 단백질은 모체탈락막세포에서 분비되는 주요 단백질 중의 하나라는 점을 감안할 때 IGFBP-I이 IGF과 무관한 작용이 있을 가능성도 배제할 수 없다. 따라서 IGFBPs의 역할 규명은 IGF system을 이해하는데 중요한 부분을 차지하고 있어 향후 이 분야의 연구에 많은 기대와 촛점이 모여지고 있다.

• 한국수정란이식학회지
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• 제12권3호
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• pp.229-246
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• 1997

Implantation is a most important biological process during pregnancy whereby conceptus establishes its survival as well as maintenance of pregnancy. During the periimplantation period, both uterine endometriurn and conceptus synthesize and secrete a host of growth factors and cytokines which mediate the actions of estrogen and /or progesterone and also exert their steroid-independent actions. Growth factors expressed by the materno-conceptal unit en masse have important roles in cell migration, stimulation or inhibition of cell proliferation, cellular differentiation, maintenance of pregnancy and materno-conceptal communications in an autorcrine /paracrine manner. The present review focuses on the role of the intrauterine IGF system during periimplantation conceptus development. The IGF system comprises of IGF- I and IGF- II ligands, types I and II IGF receptors and six or more IGF-binding proteins(IGFBPs). IGFs and IGFBPs are expressed and secreted by uterine endometrium with tissue, pregnancy stage and species specificities under the influence of estrogen, progesterone and other growth factor(s). Conceptus also synthesizes components of the IGF system beginning from a period between 2-cell and blastocyst stages. Maternal IGFs are utilized by both maternal and conceptal tissues; conceptus-derived growth factors are believed to be taken up primarily by conceptus. IGFs enhance the development of both maternal and conceptal compartments in a wide range of biological processes. They stimulate proliferation and differentiation of endometrial cells and placental precursor cells including decidual transformation from stromal cells, placental formation and the synthesis of some steroid and protein hormones by differentiated endometrial cells or placenta. It is also well-documented in a number of experimental settings that both IGFs stimulate preimplantation embryo development. In slight contrast to these, prenatal mice carrying a null mutation of IGF and /or IGF receptor gene do not exhibit any apparent growth retardation until after implantation. Reason (s) for this discrepancy between the knock-out result and the in vitro ones, however, is not known. IGFBPs, in general, are believed to inhibit IGF action within the materno-conceptal unit, thereby allowing endometrial stromal cell differentiation as well as dampening ex cessive placental invasion into maternal tissue. There is evidence, however, indicating that IGFBP can enhance IGF action depending on environrnental conditions perhaps by directioning IGF ligand to the target cell. There is also a third possibility that certain IGFBPs and their proteolytic fragments may have their own biological activities independent of the IGF. In addition to IGFBPs, IGFBP proteases including those found within the uterine tissue or lumen are thought to enhance IGF bioavailability by degrading their substrates without affecting their bound ligand. In this regard, preliminary results in early pregnant pigs suggest that a partially characterized IGFBP protease activity in uterine luminal fluid enhances intrauterine IGF bioavailability during conceptus morphological development. In summary, a number of in vitro results indicate that IGFs stimulates the development of the rnaterno-conceptal unit during the periimplantation period. IGFBPs appear to inhibit IGF action by sequestering their ligands, whereas IGFBP proteases are thought to enhance intrauterine bioavailability of IGFs. Much is remaining to be clarified, however, regarding the roles of the individual IGF system components. These include in vivo evidence for the role of IGFs in early conceptus development, identification of IGF-regulated genes and their functions, specific roles for individual IGFBPs, identification and characterization of IGFBP proteases. The intrauterine IGF club house thus will be paying a lot of attention to forthcoming results in above and other areas, with its door wide-open!

• 한국가축번식학회지
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• 제23권3호
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• pp.213-220
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• 1999

산자수는 돼지의 번식능력에 있어 경제적 형질 중 중요한 요인으로 작용하고 있다. 최근 IGF-Ⅰ이 임신유지와 태아의 성장발달에 역할을 하는 것은 보고되어 있으나 산자수에 따른 혈청 IGF-Ⅰ연구는 부족한 상태이다. 그러므로 본 연구는 돼지의 산자수 그룹에 따른 혈청 IGF-I 농도 및 산자수에 관여하는 ER 유전자 다형성 분석을 통해 혈청 IGF-Ⅰ 농도에 대한 조사를 하고자 한다. 혈청은 산자수 높은 그룹과 낮은 그룹의 임신 45일부터 105령일 까지 모아 RIA로 IGF-Ⅰ의 농도를 측정하였으며 측정결과 두 그룹간에 유의적인 차이는 보이지 않았으나 점차적으로 떨어지는 경향을 보여 주었다. 또한 ER 유전자 다형성 분석에 따른 혈청내 IGF-Ⅰ농도는 산자수 낮은 그룹을 나타내는 단편의 IGF-Ⅰ농도가 높게 나타내는 단편에 IGF-Ⅰ농도보다 높게 나타났다. 따라서 본 연구를 통해 돼지의 내분비 물질 중 혈청내 IGF-Ⅰ이 돼지의 산자수와는 관련이 없으나 ER의 발현을 동시에 관찰한다면 돼지 산자수률 예측할 수 있다는 가능성을 제시할 수 있으며, 돼지의 번식기관 중 배란율에 관여하는 난소의 IGF-Ⅰ발현양상 등의 연구가 추후 진행될 필요가 있다고 사료된다.