• 대한수의학회지
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• 제43권3호
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• pp.383-392
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• 2003

Insulin-like growth factors (IGFs) and their binding proteins (IGFBPs) are important regulators on the development of maternal tissues during pregnancy. This study was performed to examine the relationship between maternal IGFs/IGFBPs system (i.e: IGF-I, II, their receptors, and IGFBPs) in pre- and post-partum rats. The liver and kidney are important organs for the synthesis of IGFs and IGFBPs in adults. The levels of materanal IGFs and IGFBPs in serum, liver, and kidney were examined at 14 and 21 days of gestation and at 3, 7, 11, and 14 days after birth. The expression of IGFs and their receptors mRNA was also examined in fetal and maternal rat liver, kidney. IGF-I concentrations in maternal serum and liver were decreased during pregnancy. However, IGF-I concentration in maternal kidney was increased, having maximal effect at 14 days of gestation. IGF-I concentrations were decreased in serum, liver, and kidney of postpartum rat, compared to control (p < 0.05). On the other hand, IGF-II concentrations in serum, liver, and kidney were increased during pregnancy (p<0.05) and gradually decreased to control level in postpartum period. The levels of IGFBP-3 and IGFBP-2 are expressed in serum, liver, and kidney. However, IGFBP-3 is mainly expressed in serum and liver, and IGFBP-2 in kidney. The levels of IGFBP-3 and IGFBP-2 in maternal serum were markedly decreased during pregnancy and gradually recovered to control level during postpartum period by western ligand blotting. However, there was no change of IGFBP-3 and IGFBP-2 levels by western immunoblotting. The levels of IGFBP-3 and IGFBP-2 in maternal liver and kidney also showed the same pattern of serum, although the main IGFBP is different. In normal rat serum, IGF-I 150 kDa and 50 kDa carrier proteins were detected. The level of IGF-I 150 kDa carrier proteins in pregnant rat was decreased compared to normal rat, but that of 50 kDa carrier proteins was increased. IGFBP-3 protease activity was identified in pregnant rat serum and maternal placenta, and it was inhibited by EDTA ($Ca^{2+}$ chelating agent) and aprotinin (serine proteinase inhibitor). Taken together, these results suggest that the changes of IGFs and IGFBPs in maternal rats are regulated by liver and kidney IGFs and their receptors mRNA during the pregnancy.

• 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!

• 대한의생명과학회지
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• 제10권3호
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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.

• Asian-Australasian Journal of Animal Sciences
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• 제18권11호
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• pp.1575-1581
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• 2005

This study was conducted to determine the characteristics of IGFBPs in plasma of steers, and to profile the relationship between growth and plasma IGF-1 and IGFBPs with aging in Holstein steers. Four blots of IGFBP at molecular weights of 38-43, 34, 29-32 and 24 kDa bands were detected by western ligand blot assay using $^{125}I-IGF-1$. On the basis of immunoblotting with anti-bovine IGFBP-2 and -3 antiserums, we observed the band for IGFBP-2 at approximately 34 kDa, and the IGFBP-3 band was detected at 38-43 kDa and 34 kDa in adult steers and calves. The IGFBP-3 antiserum used on the blots exhibited significant cross-reactivity with 34 kDa IGFBP-2. Furthermore, the 38-43 kDa IGFBP-3 bands were reduced to a 36 kDa band after deglycosylation, whereas the 34 kDa IGFBP-2 was intact. The plasma IGF-1, IGFBP-3 and other IGFBPs showed stability throughout a whole day. The change in live weight was found to be positively correlated to the plasma IGF-1 concentration (r = 0.6801, n = 64, p<0.05) and plasma IGFBP-3 (r = 0.6321, n = 64, p<0.05), while inversely correlated to plasma IGFBP-2 (r = -0.2919, n = 64, p<0.05). Furthermore, plasma IGF-1 was positively correlated to plasma IGFBP-3 (r = 0.6191, p<0.001), but was not correlated to plasma IGFBP-2. The portion of IGFBP-2 for total IGFBPs in calves was higher than in adult steers (p<0.05) and was decreased with growth, whereas that of IGFBP-3 was increased with increased live weight (p<0.05). The ratio IGFBP-3 for IGFBP-2 (BP-3/BP-2) was increased with growing of liveweight. Therefore, the changes in plasma IGF-1 level with increased liveweight may be related to the changes in plasma IGFBP-3 level and IGFBP-2 may give an important role in anabolic action of IGF-1 with the growth of body during calfhood in Holstein steers.

• 대한의생명과학회지
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• 제12권3호
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• pp.217-224
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• 2006

It has been reported that the dysfunctions of podocytes are associated with the development of diabetic nephropathy. In addition, insulin-like growth factors (IGFs) are associated with the development of diabetic nephropathy. However, it is not yet known about the effect of high glucose on IGF-I, -II secretion, and IGF binding proteins (IGFBPs) expression in the podocytes. Thus, this study was conducted to examine the effect of high glucose on IGF system and its involvement of protein kinase C (PKC) and mitogen activated protein kinases (MAPKs) in podocytes. In this study, high glucose (25 mM) increased IGF-I and IGF-II secretion (P<0.05), which was blocked by SB 203580 (a p38 MAPK inhibitor) but not by PD 98059 (a p44/42 MAPK inhibitor). In addition, high glucose-induced stimulation of IGFs was blocked by bisindolylmaleimide I and staurosporine (protein kinase C inhibitors). High glucose also increased IGFBP-l expression, which was blocked by bisindolylmaleimide I and SB 203580. In conclusion, high glucose alters IGFs secretion and IGFBP expression via PKC and p38 MAPK pathways in podocytes.

• Asian-Australasian Journal of Animal Sciences
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• 제21권9호
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• pp.1244-1251
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• 2008

The aim of the present study was to delineate the expression and secretion of insulin-like growth factor (IGF) system components by pig liver cells. Hepatocytes were prepared from 3-wk-old weanling piglets following a two-step collagenase perfusion procedure, after which the cells were incubated for 24 or 48 h at a density of $2{\pm}10^5$ cells per 35-mm dish in 2-ml Williams' medium E. The cells were found to express the genes encoding IGF-I, IGF-binding proteins (IGFBPs)-2 and -3 and acid-labile subunit (ALS) by reverse transcription-polymerase chain reaction (RT-PCR) following the culture. However, IGF-I was localized to hepatocytes by immunohistochemical analysis, whereas IGFBP-3 was localized to endothelial cells, but not to hepatocytes. This indicated that the IGFBP-3 gene expression detected by RT-PCR was likely to have been contributed by unidentified non-parenchymal cells that had not been removed during the hepatocyte preparation. The conditioned culture medium (CCM) of the cells contained immunoreactive IGF-I and IGF-II, with the latter being seven-fold more abundant than the former. The CCM also contained 43-, 40-, 34-, 31-kDa doublet and 26-kDa IGFBPs as examined by Western ligand blotting. The 40-, 34- and 31-kDa doublet IGFBPs were approximately three-fold as abundant as the 43- and 26-kDa IGFBPs. Moreover, the 43- and 40-kDa doublet and the 34-kDa IGFBPs were immunoprecipitable with IGFBP-3 and IGFBP-2 antibodies, respectively. Overall, these results are similar to those known in the rat, which suggests that the IGF system components are likely to be expressed and secreted in pig liver in a manner similar to that in rat liver.

• Clinical and Experimental Reproductive Medicine
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• 제26권1호
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• pp.67-73
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• 1999

The insulin-like growth factor (IGF)s are believed to one of several growth factors that play an adjunctive role in ovarian follicular development. These factors circulate bound to a family of IGF-binding protein (IGFBP)s. It is known that circulating IGFBPs are involved in the transport of IGFs to tissues and modulate IGFs actions at local tissue. The purposes of this study were to evaluate changes in serum IGFBPs profiles during normal ovulatory menstrual cylce and to compare serum IGFBPs profiles in periovulatory phase of between normal ovulatory menstrual cylce and controlled hyperstimulated cycle. Fasting blood samples were obtained from 15 normal healthy women throughout normal ovulatory menstural cyle and on the day of aspiration of oocyte from 10 patients undergoing ovarian hyperstimuation for in vito fertilization-embryo transfer. Serum IGFBP-1 - IGFBP-4 were measured by western ligand blot and immunoprecipitation. Serum $17{\beta}$-estradiol was determined by radioimmunoassay. Type and molecular weight of serum IGFBP did not changed during normal ovulatory menstural cycle. No significant variation in the relative proportion and level of each IGFBP was found throughout normal ovulatory menstural cyle. Also, the relative proportion and level of each IGFBP did not correlated with serum $17{\beta}$-estradiol level. There was no significant difference in the relative proportion and level of each serum IGFBP between on the day of ovulation in normal ovulatory menstrual cylce and on the day of aspiration of oocyte in controlled hyperstimulated cycle. Our data indicate that IGFBPs have regulatory functions in ovary through an paracrine and autocrine rather than endocrine mechanism during normal ovulatory menstural cycle.

• 현장농수산연구지
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• 제22권1호
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• pp.5-13
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• 2020

생체 조직 내에서 표지인자의 발견은 해당 세포의 특성과 기능을 이해하는 데 매우 중요하다. 기존에 밝혀진 돼지 정원세포의 표지인자로는 PGP9.5, PLZF, NANOG, SSEA1 등의 단백질이 알려져 있다. 본 연구에서는 최근 새로이 발굴된 돼지 정원세포 표지인자인 IGFBPs 의 기능을 분석하기 위해 IGFBPs 의 발현과 이를 조절하는 단백질인 PAPP-A 단백질의 발현을 5일령 돼지 정소에서 확인하였다. IGFBP 2, 3, 4, 6 의 발현이 돼지 정원세포 특이적으로 높게 나타났으며 PAPP-A의 발현은 세르톨리세포 특이적으로 나타났다. PAPP-A 의 발현을 PGP9.5, GATA4 등의 표지 인자와 함께 확인해 본 결과 PGP9.5를 발현하는 정원세포에서는 발현하지 않았으며, 세정관 내의 세르톨리세포 특이적으로 발현하였다. 이러한 사실로 미루어 볼 때 세르톨리세포에서 발현하는 PAPP-A 단백질은 정원세포에서 발현하는 IGFBPs 의 조절을 통하여 알려진 바와 같이 IGF axis 를 통해 정소내 세포들의 발달 및 분화를 조절할 것으로 판단된다.

• Journal of Nutrition and Health
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• 제36권3호
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• pp.270-279
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• 2003

Conjugated linoleic acid (CLA) is a group of positional and geometric isomers of linoleic acid (LA) and exhibits anticarcinogenic activity in a variety of animal models. We have previously observed that CLA inhibited the growth of Caco-2 cells, a human colon adenocarcinoma cell line. The present study was performed to determine whether the growth inhibitory effect of CLA is related to change in secretion of IGF- II and/or IGF-binding proteins (IGFBPs) that have been shown to regulate Caco-2 cell proliferation by an autocrine mechanism. Cells were incubated in serum-free medium with various concentrations of CLA or linoleic acid (LA). Immunoblot analysis of 24-hours, serum-free, conditioned medium using a monoclonal anti-IGF-IIantibody revealed that Caco-2 cells secreted both mature 6,500 Mr and higher Mr forms of pro IGF-II. The levels of pro IGF-II and mature IGF-IIwere decreased by 43 $\pm$ 2% and 53 $\pm$ 6%, respectively by treatment with 50 $\mu$ M CLA. LA slightly increased pro IGF- II levels. Results from Northern blot analysis showed that CLA decreased IGF-II mRNA levels at 50 $\mu$ M concentration suggesting that CLA regulation of IGF-II protein expression occurs partly at the transcriptional level. Ligand blot analysis of conditioned media using 1251-IGF-II revealed that CLA slightly decreased IGFBP-2 levels and increased IGFBP-4 levels. We confirmed our previous results that CLA inhibited cell growth in a dose-dependent manner but LA slightly increased cell growth. Exogenous IGF-II mitigated the growth inhibitory effect of CLA. These results indicate that the growth inhibitory effect of CLA may be at least in part mediated by decreasing IGF-II and IGFBP-2 secretion and increasing IGFBP-4 secretion in Caco-2 cells.

• 생명과학회지
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• 제18권7호
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• pp.931-939
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• 2008

본연구는 정상으로 단백질을 급여한 거세면양에 있어서 에너지 첨가가 GHRP-2투여에 대한 IGF-1 및 IGFBPs에 대한 반응과, 고에너지 급여에 따른 GHRP-2투여가 hepatic GH 수용체에 미치는 영향을 검증하기 위하여 실시하였다. 시험 결과 HENP (CP 0.34 kg, TDN 1.83 kg/day DM intake)처리기간 동안 혈장 IGF-1 과 39-42kDa IGFBP-3수준은 LENP (CP 0.32 kg, TDN 0.87 kg/day DM intake)기간에 비하여 높게 나타났으나 (P<0.05), 혈장 34 kDa IGFBP-2와 24 kDa IGFBP-4는 영양처리에 의해 영향을 받지 않았다. 각 영양처리 기간동안 GHRP-2 ($12.5\;{\mu}g/kg$ body weight/day)투여는 혈장 GH 반응이 촉진되었으며(P<0.05), 혈장 GH 평균 함량과 AUC증가에 있어서는 LENP처리 기간에 비하여 HENP처리기간에서 유의적으로 높게 나타났다(P<0.01). 특히 HENP에서 7일간 GHRP-2투여에 의한 일중 혈장 IGF-1 변화양상을 조사한 결과 투여 2, 6 및 7일에서 뚜렷한 증가양상이 보였다(P<0.05). 이에 반하여 LENP에서는 오직 투여 3일째에서 Saline구에 비하여 유의적인 증가를 확인하였다(P<0.05). IGFBPs의 ligand blotting 결과 HENP구에서 혈장 39-43 kDa IGFBP-3의 수준의 증가가 투여 6일과 7일에서 관찰되었으나 혈장 IGFBP-2수준은 두 영양처리시기에서 유의적인 차이를 관찰하지 못했다. 아울러 HENP구에 있어서 간세포막에 $^{125}I-oGH$의 결합력을 측정한 결과 GHRP-2투여에 의한 영향은 관찰되지 않았다. 이와 같은 결과는 거세면양에 있어서 단백질과 에너지 사이에 영양적 균형은 내인성 GH/IGF-1 axis는 물론 혈장 IGFBP-3수준의 변화에 영향을 미치고 있음을 시사한다.