Accuracy of different biomarkers for early diagnosis of acute kidney injury in patients undergoing cardiovascular surgery under cardiopulmonary bypass / 中华麻醉学杂志

Objective To evaluate the accuracy of different biomarkers for early diagnosis of acute kidney injury ( AKI ) in the patients undergoing cardiovascular surgery under cardiopulmonary bypass ( CPB) . Methods A total of 200 patients, aged 22-86 yr, weighing 46-87 kg, scheduled for elective cardiovascular surgery under CPB, were enrolled in this study. The concentration of serum creatinine was determined at 1 day before operation and 1-7 days after operation. At 1 day before operation and 0, 2, 6 and 12 h after operation, the concentrations of urine neutrophil gelatinase-associated lipocalin (NGAL), cystatin C ( Cys C) , tissue inhibitor of matrix metalloproteinase type 2 ( TIMP-2) and insulin-like growth factor binding protein-7 ( IGFBP-7) were determined. The TIMP-2 and IGFBP-7 product ( TI) was calcu-lated. AKI was diagnosed after surgery according to Kidney Disease Improving Global Outcomes criteria. The receiver operating characteristic curve was plotted, and the area under receiver operating characteristic curve ( AUC) was calculated. Results The incidence of AKI was 20. 5％. The AUC of AKI diagnosed by the concentration of urine NGAL was 0. 689, 0. 709, 0. 713 and 0. 803 at 0, 2, 6 and 12 h after opera-tion, respectively ( P<0. 05) . The AUC of AKI diagnosed by the concentration of urine Cys C was 0. 639, 0. 762, 0. 774 and 0. 812 at 0, 2, 6 and 12 h after operation, respectively ( P<0. 05) . The AUC of AKIdiagnosed by TI was 0. 687, 0. 721, 0. 740 and 0. 779 at 0, 2, 6 and 12 h after operation, respectively ( P<0. 05) . The AUC of AKI diagnosed by combined three indices the parallel test was 0. 694, 0. 773 and 0. 794 at 0, 2 and 6 h after operation, respectively ( P<0. 05) . The AUC of AKI diagnosed by the serial test was 0. 610, 0. 631 and 0. 667 at 0, 2 and 6 h after operation, respectively. Conclusion Urine NGAL or Cys C concentrations or TI single detection and parallel test have a certain accuracy for early diag-nosis of AKI in the patients undergoing cardiovascular surgery under CPB.

Asociación entre el sistema IGF y PAPP-A en ateroesclerosis coronaria / Association between IGF system and PAPP-A in coronary atherosclerosis

Resumen La aterosclerosis es una enfermedad que involucra múltiples mecanismos fisiopatológicos cuyo conocimiento no se ha dilucidado por completo. Con frecuencia, los avances científicos sobre la fisiopatología aterogénica generan que a diversas moléculas no consideradas previamente en el panorama de dicha enfermedad se les atribuyan acciones sobre el inicio o progresión de la misma. Un ejemplo representativo es el estudio de un nuevo mecanismo involucrado en el proceso aterogénico, consistente en la asociación entre el sistema de factores de crecimiento similares a la insulina (IGF) y la proteína plasmática A asociada al embarazo (PAPP-A). El sistema IGF es una familia de péptidos compuesto por 3 hormonas peptídicas, 4 receptores transmembranales y 6 proteínas transportadoras. El factor de crecimiento similar a la insulina tipo 1 (IGF-1) es el principal ligando del sistema IGF involucrado en la aterosclerosis coronaria y ejerce sus efectos mediante la activación del receptor IGF-1R en células de músculo liso vascular de las arterias coronarias o en macrófagos de placas ateroscleróticas. En células de músculo liso vascular promueve la migración y previene la apoptosis aumentando la estabilidad de la placa, y en macrófagos disminuye el transporte reverso de colesterol propiciando la formación de células espumosas. La regulación de la biodisponibilidad de IGF-1 en el endotelio se lleva a cabo por las proteasas de proteínas IGFBP, principalmente por la PAPP-A. En la presente revisión se abordan los mecanismos involucrados entre el sistema IGF y la PAPP-A en aterosclerosis coronaria con énfasis en los efectos moleculares producidos en células de músculo liso vascular y en macrófagos.

Abstract Atherosclerosis is a condition that involves multiple pathophysiological mechanisms and whose knowledge has not been fully elucidated. Often, scientific advances on the atherogenic pathophysiology generate that molecules not previously considered in the scene of this disease, were attributed actions on the onset or progression of it. A representative example is the study of a new mechanism involved in the atherogenic process, consisting of the association between the insulin-like growth factor (IGF) system and pregnancy-associated plasma protein-A (PAPP-A). Insulin-like growth factor system is a family of peptides that include 3 peptide hormones, 4 transmembrane receptors and 6 binding proteins. Insulin-like growth factor-1 (IGF-1) is the main ligand of the IGF system involved in coronary atherosclerosis. IGF-1 exerts its effects via activation of the IGF-1R receptor on vascular smooth muscle cells or macrophages. In vascular smooth muscle cells promotes migration and prevents apoptosis which increases plaque stability while in macrophages reduces reverse cholesterol transport leading to the formation of foam cells. Regulation of IGF-1 endothelial bioavailability is carried out by IGFBP proteases, mainly by PAPP-A. In this review, we address the mechanisms between IGF system and PAPP-A in atherosclerosis with emphasis on molecular effects on vascular smooth muscle cells and macrophages.

Effect of IGFBP-3 in the Inhibition of Gastric Carcinoma Cells Proliferation byResveratrol / 医药导报

Objective To study the expression of insulin like growth factor binding proteins 3 (IGFBP-3) during inhi-bition of resveratrol (Res) on cell proliferation. Methods The inhibitory effect of Res on BGC-823 cells was determined by MTT method; Real-time qRT-PCR and western blot were applied to detect the expression of IGFBP-3 in Res-treated BGC-823 cells. In addition, cytometry was used to determine the proliferation and apoptosis of Res-treated BGC-823 after knockdown of IG-FBP-3 by siRNA. Results Upon Res (20,40, 80 and 160 μmol · L-1 ) treatment,the viability of BGC-823 cells was (82. 35±10. 65)% ,(74. 30±12. 36)% ,(62. 80±14. 66)% and (50. 75±11. 14)% , respectively. The mRNA and protein ex-pression of IGFBP-3 elevated as high as 2. 96-fold compared to the control group (P<0. 05). The cell viability of BGC-823 cells with IGFBP-3 knockdown was significantly higher than that of the wild type ( P < 0. 05 ) only at high Res concentration (160 μmol·L-1 ). Meanwhile,IGFBP-3 knockdown led to a significant decrease on cell apoptotic rate by Res (160 μmol·L-1 ) [(20. 13±9. 12)% vs (35. 48±11. 12)% ,P<0. 05)]. Conclusion Res can inhibit BGC-823 cell proliferation and promote cell apoptosis, the underlying mechanism of which may be related to the overexpression of IGFBP-3 in BGC-823 cells.

In vitro effects of acitretin on the apoptosis and expressions of insulin-like growth factor binding protein 7 and vascular endothelial growth factor in HaCaT cells / 中华皮肤科杂志

Objective To investigate the in vitro effects of acitretin on the apoptosis and expressions of insulin-like growth factor binding protein 7 (IGFBP7) and vascular endothelial growth factor (VEGF) in HaCaT cells.Methods Cultured HaCaT cells were treated with various concentrations (10-5,10-64,10-7,10-8 mol/L) of acitretin for various durations,with those cultured in acitretin-free medium serving as the control group.Then,CCK-8 assay was performed to evaluate the proliferation of cells after 24-,48-and 72-hour treatment,flow cytometry to detect the apoptosis of HaCaT cells,and Western blot and reverse transcription-PCR to quantify the protein and mRNA expressions of IGFBP7 and VEGF in HaCaT cells,respectively,after 48-hour treatment.Statistical analysis was carried out by one-way analysis of variance and Pearson correlation analysis.Results The proliferation of HaCaT cells was inhibited by the treatment with acitretin,and the inhibitory effect increased with the elevation of concentration and prolongation of treatment duration of acitretin.A significant decrease was observed in the proliferative activity of HaCaT cells treated with acitretin of 10-8 mol/L for 48 hours,and when the concentration of acitretin was 10-5 mol/L,the proliferation of HaCaT cells was inhibited by 39.94％ ± 2.27％ and 49.77％ ± 1.87％ at 48 and 72 hours respectively,compared with the control cells.The HaCaT cells treated with acitretin of 10-5 mol/L for 48 hours showed a significant elevation in apoptosis rate (7.617％ ± 0.767％ vs.1.803％ ± 0.313％,P ＜ 0.05),IGFBP7 protein and mRNA expressions (0.939 ± 0.040 vs.0.436 ± 0.013,0.872 ± 0.079 vs.0.190 ± 0.056,both P ＜ 0.05),but a significant reduction in VEGF protein and mRNA expressions (0.213 ± 0.032 vs.0.798 ± 0.036,0.274 ± 0.041 vs.0.933 ± 0.054,both P ＜ 0.05) in comparison to the control cells.Conclusions Acitretin can induce the apoptosis of HaCaT cells,and up-regulate IGFBP7 but down-regulate VEGF expressions in HaCaT cells at protein and mRNA levels.

The levels of insulin-like growth factors in children with acute leukemia / 临床儿科杂志

Objective To detect the levels of insulin-like growth factors in children with acute leukemia (AL). Methods A total of 50 previously untreated AL patients were selected, meanwhile 30 healthy children were selected as normal controls. AL children were given regular chemotherapy. All cases were not given the brain radiotherapy. The levels of insulin-like growth factor-1 (IGF-1), free insulin-like growth factor-1 (fIGF-1), insulin-like growth factor binding protein 3 (IGFBP-3) in AL patients before treatment and 6 months after complete remission were measured by enzyme-linked immunosorbent assay (ELISA), and were compared with those in normal controls. Results Before treatment, compared with normal controls, the serum levels of IGF-1, IGFBP-3 in AL patients were lower while the level of fIGF-1 was higher, and the differences were signiifcant (P<0.01). At six months after complete remission, the levels of IGF-1 and fIGF-1 in AL patients were similar to those before treatment, but were signiifcantly different from those in control group (P<0.05);the level of IGFBP-3 was signiifcantly higher than that before treatment (P<0.01), but was similar to that in control group. Before treatment, the level of IGFBP-3 in AL patients was positively correlated with the level of IGF-1 (r=0.777, P<0.01), and negatively correlated with the level of fIGF-1 (r=-0.714, P<0.01). Conclusion Insuline-like growth factors were involved in the pathophysiological process in children with AL.

Influences of Maixiansan on insulin-like growth factor hinding protein7 and apoptosis in rats with ulcerative colitis-related colorectal cancer / 中华老年医学杂志

Objective To invcstigate the effects of Maixiansan on insulin-like growth factor binding protein 7 (IGFBP7) and apoptosis in rats with ulcerative colitis related colorectal cancer.Methods The rat model of ulcerative colitis-related coloreetal cancer was induced by dextran sulfate sodium (DSS) and azoxymethane(AOM). 40 male SD rats [weight (160 ± 10) g] were randomly divided into 4 groups: model, Maixiansan and Meisalazine treatment as well as normal group peritoneally irjected with saline.The expression of IGFBP7 and apoptosis in coloreetal tissue were detected by real-time PCR and TUNEL after 16 weeks. Results The numbers of colorectal cancer in model group( 1.2 ± 0.4 ),in Maixiansan group ( 0.70 ± 0.15 ),in Meisalazine group ( 0.60 ± 0.16 )were higher than in normal control (P ＜ 0.05), but no differences were found among model,Maixiansan and Meisalazine groups(P＞0.05).The apoptosis in colonic mucosa for Meixiansan(8.70±3.47) group and Mesalazine group were enhanced as compared with that in model group( 1.20 ±0.26 vs.0.38±0.11,P＜0.05).The mRNA expression of IGFBP7 in colon for Meixiansan group were higher than those in model group,Meisalazine group,and normal control(50.5 ± 14.0 vs.18.0 ±3.9 and 39.3±11.4,46.4±6.0,P＜0.05). Conclusions Maixiansan may resist the occurrence and development of ulcerative colitis-related colorectal cancer through upregulating IGFBP7 expression of colorectal tissue and promoting apoptosis of tumor cell.

O Sistema do Hormônio de Crescimento: interações com a pele / Growth Hormone System: skin interactions

O artigo descreve o Sistema do Hormônio de Crescimento (GH), enfatizando suas possíveis ações nas células da epiderme, nas estruturas da derme e na cicatrização de feridas cutâneas. Para tanto, fez-se uma revisão dos conhecimentos sobre o hormônio do crescimento, seu receptor, a proteína carreadora deste hormônio e demais proteínas envolvidas no mecanismo que o GH utiliza para a sua manifestação nos tecidos cutâneos.

This paper describes the growth hormone system, emphasizing its possible effects on epidermal cells, dermal structures and wound healing. A review of the literature was conducted on studies concerning the growth hormone molecule, its receptor and carrier proteins and the other proteins involved in the mechanisms of its manifestation in dermal tissue.

Progress in the research of insulin-like growth factor family in lung cancer / 肿瘤

Insulin-like growth factors (IGF), regulated by their receptors and binding proteins, play a pivotal role in human cell proliferation, differentiation and apoptosis. Increasing evidence has revealed that IGF system is involved in the genesis and progress of various malignancies including lung cancer. Recent studies in regard to IGF axis expression in the lung cancer cell lines, pulmonary tissue samples and blood circulation of lung cancer patients have shown that the IGF axis may contribute to the transformation and progression of lung cancer. Several researches have shown that a number of drugs targeting the IGF receptor are being investigated in clinical trials and suggest a potential therapeutic efficacy. This article reviews the updates and progress in the research of IGF axis in lung cancer.

Expression of the Insulin-like Growth Factor Binding Proteins (IGFBPs) in Colon Cancer

PURPOSE: The purpose of this study was to demonstrate the hypothesis that tussue IGFBP-2,-3, and -4 levels would differ between colon cancer tissue and adjacent normal tissue and to determine whether these factors could affect the clinicopathologic characteristics such as age, tumor stage, differentiation, serosal invasion, and CEA in patients with colon cancer. METHODS: This study group consisted of 102 patients with colorectal cancer who under went operations between January 2004 and December 2006. Postoperative colon cancer specimens and adjacent normal colon tissues were obtained immediately. Histopathologic examinations were made by on pathologist for each specimen. The gene expressions of IGFBP-2,-3,-4 in cancer and normal tissues were measured using a reverse transcriptase-polymerase chain reaction (RT-PCR). In additional, the various clinic-opathologic factors were evaluated for both tissues by comparing the IGFBP-2, -3, -4 expression densities. RESULTS: No significant difference was found in the expression of IGFBP-3, -4 between colon cancer and normal colon tissues. A statistically significant expression of IGFBP-2 was detected in the cancer specimens compared with the normal colon tissues. IGFBP-3 was significantly associated with pathologic N stage. CONCLUSIONS: This is a rare report comparing colon cancer with normal colon tissue for IGFBP expression by means of a systemical evaluation of colon cancer patients. Our data suggest that IGFBP-2 may be intimately associated with malignant phenotypes, and may confer some growth advantage on tumor cells, which means that IGFBP-2 shows a high sensitivity for colorectal cancer. Interestingly, IGFBP-3 was strongly associated with the pathologic N stage. We think further studies are needed to understand this phenomenon.

The Tumor Suppressor Function of PTEN/MMAC1 through the Regulation of IGFs and IGFBPs / 소아과

PURPOSE: PTEN/MMAC1, a novel tumor suppressor gene, is mutated in a variety of advanced and metastatic cancers. It acts as a phosphatase, and thereby, regulates the PI-3 kinase/Akt pathway. In this study, we examined to evaluate the new function of anti-tumor effects of PTEN/MMAC1 through the regulation of the IGFs-IGFBPs in gastric cancer cells. METHODS: PTEN/MMAC1 was expressed in an adenovirus-mediated gene delivery system and introduced into gastric cancer cells(SNU-484 & SNU-668) in vitro. The effect of cell growth and the expression of IGFs and IGFBPs after Ad/PTEN infection was analyzed by MTT assay, RT-PCR and Western immunoblot. RESULTS: Ad/PTEN infected cells were inhibited in cell growth compared with moak cells and Ad/ LacZ infected cells. Overexpression of PTEN/MMAC1 induced decrease in expression of IGF-I, -II and IGF-I receptors which are known as growth prompt molecules in a variety of cancers. Of the six IGFBPs, the expressions of IGFBP-4 and IGFBP-6 were decreased in Ad/PTEN infected cells. In contrast, IGFBP-3 expression was markedly increased by up to 3-fold in Ad/PTEN infected cells. Overexpression of PTEN/MMAC1 inhibited the activation of Akt/PKB pathway, but had no effect on the MAPK pathway. CONCLUSION: These findings suggest that the tumor suppressor function of PTEN/MMAC1 is, at least in part, mediated through the down-regulation of IGF-I abd IGF-II, and up-regulation of IGFBP-3 in gastric cancer cells by the inhibition of PI-3 kinase pathway.

Study of the Mechanism for the Growth Inhibitory Effects of Conjugated Linoleic Acid on Caco-2 Colon Cancer Cells

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+/-2% and 53+/-6%, respectively by treatment with 50 micrometer CLA. LA slightly increased pro IGF- II levels. Results from Northern blot analysis showed that CLA decreased IGF-II mRNA levels at 50 micrometer 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.

The Changes of Growth Hormone, Insulin-like Growth Factor-1 and Insulin-like Growth Factor Binding Protein-3 Levels after Long-Term Dialysis Therapy / 대한신장학회잡지

The insulin-like growth factor-I(IGF-I) is a hormone that has growth stimulation and metabolic effects. Insulin-like growth factor binding proteins (IGFBPs) were known to be the most important factors that affect bioavailability of IGF. Thereby, the changes of IGFBPs may affect the bioavailability of IGF-I. Because growth hormone/IGF system may be affected by dialysis therapy, the changes of GH, IGF-1, IGFBPs levels after dialysis therapy can affect the bioavailability of IGF. To evaluate the changes of serum levels of IGF-I and IGFBP-3 after long-term dialysis therapy, we measured the serum IGF-I and IGFBP-3 levels in the patients on hemodialysis and on peritoneal dialysis. Eight patients undergoing peritoneal dialysis, 10 patients undergoing hemodialysis, and age-matched 10 normal control patients were studied. In patients on hemodialysis, the mean serum level of IGF-I before hemodialysis was 90.6+/-9.0 nanogram/mL, and after long-term hemodialysis was 130.9+/-31.0 nanogram/milliliter. The mean serum level of IGFBP-3 before hemodialysis was 14,549+/-7,815 microgram/liter, and after long-term hemodialysis was 5,726+/-883 microgram/liter. There were no significant changes of serum IGF-I and IGFBP-3 levels after long-term hemodialysis therapy. In patients on peritoneal dialysis, the mean serum level of IGF-I before peritoneal dialysis was 169.8+/-20.5 nanogram/milliliter, and after long-term peritoneal dialysis was 242.6+/-37.6 nanogram/mL. The mean serum level of IGFBP- 3 before peritoneal dialysis was 10,272+/-885 microgram/liter, and after ling-term peritoneal dialysis was 8,604+/-1,721 microgram/liter. There were no significant changes of serum IGF-I and IGFBP-3 levels after long-term peritoneal dialysis. We found that the level of IGF-1 before hemodialysis was lower then that of normal control group and the level of IGFBP-3 before hemodialysis or peritoneal dialysis was higher then that of normal control group. Our results suggested that the blood levels of growth hormone, IGF-I and IGFBP-3 may not be significantly affected by long-term dialysis therapy.

Effect of heparin,IGFBP-4 and IGF-1 on glucose metabolism and function in fibroblasts / 中国病理生理杂志

AIM: To study the inhibitory effect of IGF binding protein-4(IGFBP-4),especially in corporation with heparin on the pathopoiesis of insulin-like growth factor-1(IGF-1) in alveolitis and fibrosis.METHODS: The diploid human embryonic lung(HEL) fibroblasts were incubated respectively with control,100 ?g/L IGF-1,100 ?g/L IGF-1+100 ?g/L IGFBP-4,100 ?g/L IGF-1+200 ?g/L IGFBP-4,100 ?g/L IGF-1+100 ?g/L IGFBP-4+100 ?g/L heparin,100 ?g/L IGF-1 + 100 ?g/L IGFBP-4+200 ?g/L heparin,100 ?g/L IGF-1+100 ?g/L heparin,100 ?g/L IGF-1+200 ?g/L heparin for 24 h.Then the content of glucose transporter-4(GLUT-4),hexokinase-2(HK-2),collagen-4 and elastin were detected,respectively.RESULTS: Compared with control group,HK-2,GLUT-4,elastin and collagen-4 expressed in IGF-1 group were increased obviously.The expression in the group of IGFBP-4 plus IGF-1 was more than that in IGF-1 group.However,all expression was depressed strikingly when heparin was added.CONCLUSION:(1) IGF-1 apparently stimulates HK-2,GLUT-4,elastin and collagen-IV secretions from lung fibroblasts.(2) The intact IGFBP-4 associated with heparin can inhibit the pathopoiesis of IGF-1.

Serum insulin-like growth factor (IGF)-I and IGF-binding proteins in lung cancer patients

Many studies have shown that insulin-like growth factors (IGF-I & IGF-II) are implicated in the autocrine and paracrine growth of various tumors. Alterations in serum IGFs and IGF-binding proteins (IGFBPs) profiles have been reported in lung cancer. In this study, we measured serum levels of IGF-I and IGFBPs in 41 patients with lung cancer (small cell lung cancer, SCLC, 9; non-small cell lung cancer, NSCLC, 32) by radioimmunoassay and Western ligand blot (WLB). The serum IGF-I level in patients with lung cancer was significantly lower than in controls (207.9+/-62.6 vs 281.3+/-53.9 ng/mL, p0.05). The concentration of IGFBP-3 in lung cancer was 48% of that found in controls by WLB. The serum level of IGFBP-2 was markedly elevated in patients with lung cancer compared with controls (1303.7+/-618.0 vs 696.2+/-300.5, p<0.01). However, there was no significant difference between SCLC and NSCLC groups. This result showed that serum level of IGF-I/IGFBPs may be useful markers for diagnosing and identifying tumor types in lung cancer and further studies are needed.

Expression of Insulin-like Growth Factor I (IGF-I) and Its Binding Proteins in Rat Tissues / 대한소아내분비학회지

covered with liguid nitrozen and pulverized with a pestle. To the powered tissue 5ml of 3.3M formic acid/0.5% Tween 20 was added and centrifuged at 40,000*g for 10 min. An aliquot of supernate was put into C18 sepak minicolumn to eliminates IGF-BPs. Measurement of IGF-I in rat tissues was done by RIA with anti-hIGF-I antibody and hIGF-I(PSIII) standard which was prepared by Drs. L. E. Underwood and J. J. Van Wyk UNC at Chapel Hill, NC, USA and distributed through the National Hormone and Pituitary Distribution Program. Distribution of IGF-I in rat tissue was seen by SDS-PAGE and ligand blotting method. A cDNA library in lambda gt11 of rat liver was used to isolate the cDNA of IGF-I. Phage containing inserts encoding rat IGF-I were identified by hybridization with biotin labeled synthesized oligomer which was the sequence from 1 to 8 aminoacids of known rat IGF-I. The EcoRI inserts were subcloned into PBluescript SK. The nucleotide sequence of both strands was determined by the dideoxy chain termination method. RESULTS: 1)IGF-BPs in tissue extract which could compete with antibody for IGF-I in measureing the IGF-I were eluted at 50Kdalton molecular weight marker using Protein-pak 300SW column. Using C18-sepak minicolumn, IGF-BPs were completely eliminated from tissue extract as much as possible, using Protein-pak 300SW column. 2)The amount of IGF-I in tissues was as folows: liver 575+/-41.6ng/g, lung 552.0+/-40.8ng/g. kidney 503+/-30.8ng/g, heart 449.0+/-30.4ng/g, testis 225+/-18.8ng/g, spleen 146+/-26.4ng/g, muscle 92+/-7.6ng/g and brain 49.0+/-5.8ng/g. The amount of IGF-I in blood was 1403+/-60.8ng/ml. 3)Banding patterns of IGF-BPs in rat tissues extract were obtained using ligand blotting. IGF-BP3 bands at 50 Kdalton molecular weight marker were strongly shown in testis, heart, and lung extracts but not in brain and muscle. IGF-BP1 and 2 band at 30Kdalton molecular weight marker was strongly shown in liver, kidney, spleen, testis, heart and lung. IGF-BP4 band at 21 Kdalton molecular weight marker was weakly shown only in spleen and muscle. 4) The nucleotide sequence of cloned cDNA of rat IGF-I is as follows. 5 10 15 5'----- CC CTT TGC GGG GCT GAG CTG GTG GAC GCT CTT CAG TTC GTG TGT 20 25 30 -GGA CCA AGG GGC TTT TAC TTC AAC AAG CCC ACA GGC TAT GGC- 35 40 45 -TCC AGC ATT CGG AGG GCA CCA CAG ACG GGC ATT GTG GAT GAG------3 CONCLUSION: This study suggests that tissue extraction method for IGF-I from tissues and elimination of IGF-BPs using C18 sepak minicolumn is suitable for measuring in large numbers of samples. Expression of IGF-I and IGF-BPs in multiple tissues suggests some phsiologic function at each tissue level. Subcloning of cDNA of exon 3 and 4 of IGF-I was useful for studying regulation of IGF-IA and IB mRNA in rat tissue.

Biological roles of insulin-like growth factor binding proteins (IGFBPs)

The insulin-like growth factor binding protein (IGFBP) family is a critical component of the insulin-like growth factor (IGF) system which regulate the biological actions of the IGFs and may also be capable of IGF-independent actions. To date, seven distinct IGFBPs have been described. Among these IGFBPs, IGFBPs-1-6 bind IGFs with high affinity, while only IGFBP-7 binds with low affinity. Recently, we have demonstrated that connective tissue growth factor (CTGF) also binds IGFs with low affinity, suggesting that a family of low-affinity IGFBPs, distinct from the high-affinity members, may exist, and together these constitute an IGFBP superfamily. IGFBPs have various biological roles. IGFBPs act not only as a carrier proteins, but also as a modulators of IGF actions by involving in IGF ligand-receptor interactions through influences on both the bioavailability and distribution of IGFs in the extracellular environment. In addition, some IGFBPs (IGFBPs-1, -3, and -5) appears to have intrinsic activity independent of IGFs. This review will focus on recent studies on the biological roles of IGFBPs in IGF-dependent and IGF-independent modes.