• Asian-Australasian Journal of Animal Sciences
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• 제10권2호
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• pp.233-239
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• 1997

A mammary epithelial cell line (MAC-T) established as a model for lactation was utilized to identify and characterize effects of various hormones upon insulin-like growth factor binding protein secretion. Ligand and immunoblot analyses of conditioned media indicated that insulin-like growth factor binding protein-2 was secreted by MAC-T cells. Insulin-like growth factor-I stimulated insulin-like growth factor binding protein-2 secretion in a dose-dependent manner, but prolactin and bovine somatotropin did not alter insulin-like growth factor binding protein-2 secretion. Insulin increased and cortisol decreased insulin-like growth factor binding protein-2 secretion. Effects of insulin-like growth factor-I on insulin-like growth factor binding protein-2 secretion support previous studies using primary cultures of bovine mammary cells and bovine fibroblasts. Effects of cortisol and insulin on insulin-like growth factor binding protein-2 secretion may be explained by changes in protein synthesis. In addition, supraphysiological doses of insulin can cross-react with the insulin-like growth factor-I receptor and stimulate insulin-like growth factor binding protein-2 secretion. MAC-T cells provide a model system to study mechanisms that regulate local insulin-like growth factor-I bioactivity.

• Archives of Pharmacal Research
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• 제13권4호
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• pp.355-358
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• 1990

In order to investigate the cellular mechanisms of hypoglycemic of brazilin, hepatocyte monolayer culture was introduced and, glycogen synthesis rate and insulin binding were measured as parameters. Glycogen synthesis and insulin sensitivity were remarkably augmented by the treatment of brazilin. Brazilin slightely increased insulin binding. Scatchard analysis revealed that this increase in insulin binding was not due to increase in the binding capacity but in binding affinity. These results suggest that the augmentation of hepatic glycogenesis and insulin sensitivity by brazilin may play an important role in the improvement of hyperglycemia.

• Biomolecules & Therapeutics
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• 제2권1호
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• pp.65-70
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• 1994

Hypoglycemic mechanism of brazilin was investigated in the streptozotocin induced diabetic rats. Plasma glucose levels of diabetic rats were significantly ame]iorated by the treatment of brazilin, but there were no changes in plasma insulin levels. Brazilin increased insulin binding capacity to epididymal adipocytes, and Scatchard analysis revealed that this increase in insulin binding was not due to the increase of insulin binding sites but that of binding affinity. 2-Deoxyglucose uptake of epididymal adipocytes was significantly augmented by the intraperitoneal administration of brazilin and the same result was obtained in in vitro study. Glucose oxidation and lipogenesis in epididymal adipocytes were significantly enhanced by the treatment of bracilin.

• Molecules and Cells
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• 제41권10호
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• pp.909-916
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• 2018

In pancreatic ${\beta}$ cells, glucose stimulates the biosynthesis of insulin at transcriptional and post-transcriptional levels. The RNA-binding protein, polypyrimidine tract-binding protein 1 (PTBP1), also named hnRNP I, acts as a critical mediator of insulin biosynthesis through binding to the pyrimidine-rich region in the 3'-untranslated region (UTR) of insulin mRNA. However, the underlying mechanism that regulates its expression in ${\beta}$ cells is unclear. Here, we report that glucose induces the expression of PTBP1 via the insulin receptor (IR) signaling pathway in ${\beta}$ cells. PTBP1 is present in ${\beta}$ cells of both mouse and monkey, where its levels are increased by glucose and insulin, but not by insulin-like growth factor 1. PTBP1 levels in immortalized ${\beta}$ cells established from wild-type (${\beta}IRWT$) mice are higher than levels in ${\beta}$ cells established from IR-null (${\beta}IRKO$) mice, and ectopic re-expression of IR-WT in ${\beta}IRKO$ cells restored PTBP1 levels. However, PTBP1 levels were not altered in ${\beta}IRKO$ cells transfected with IR-3YA, in which the Tyr1158/1162/1163 residues are substituted with Ala. Consistently, treatment with glucose or insulin elevated PTBP1 levels in ${\beta}IRWT$ cells, but not in ${\beta}IRKO$ cells. In addition, silencing Akt significantly lowered PTBP1 levels. Thus, our results identify insulin as a pivotal mediator of glucose-induced PTBP1 expression in pancreatic ${\beta}$ cells.

• Asian-Australasian Journal of Animal Sciences
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• 제2권3호
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• pp.218-219
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• 1989

• 한국수산과학회지
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• 제31권5호
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• pp.774-778
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• 1998

동물성장인자인 insulin-like growth factor-I (IGF-I)이 조피볼락의 성장 및 혈액중에 존재하는 IGF binding proteins (IGFBPs)에 미치는 영향을 검토하기 위하여 human recombinant IGF-I을 투여하여 분석한 결과, 절식중의 조피볼락 체중은 IGF-I 투여군이 생리식염수만 투여한 대조군 보다 체중 증가효과가 있었으며, 혈액중 glucose농도는 IGF-I의 투여군이 혈당저하효과를 나타내었다. 그리고 혈액중 IGFBP-3는 IGF-I투여군에서 증가하였으며, IGFBP-1은 감소하였다.

• 한국식품영양과학회지
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• 제28권3호
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• pp.685-690
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• 1999

The insulin like growth factors(IGFs) are bound to several binding proteins(IGFBPs) that appear to regulate IGF transfort, receptor binding, and its action. The concentrations of these peptides are regulated by quantity and nutritional quality of dietary proteins. The aim of this study was to compare the effects of two diets, which differed in their protein source, Carassius carassius(CC), Carassius carassius hot water extract(CCHE), for 4 weeks. Body weight was significantly increased in the CC group(74.14$\pm$12.00 to 266.31$\pm$36.62g; p<0.01). Likewise, IGF I concentration of CC group(101.76$\pm$15.90 ng/ml) was significantly higher than that of CCHE group(38.50$\pm$ 11.20ng/ml; p<0.05). By western immunoblot analysis, especially IGFBP 1, 2 levels are increased, whereas IGFBP 3 level was de creased in CCHE group. After extraction of browning material from each samples, the extractive was filtered and absorbance at 420nm was measured. The absorbance of CCHE group was significantly higher than that of CC group. These results suggest that IGF I can be employed as an index of protein metabolism, particulary as a simple index in the assessing the status of protein nutrition.

• 한국식품영양과학회지
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• 제29권3호
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• pp.493-499
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• 2000

골감소증 환자의 혈청중에 존재하는 IGFBP-5의 존재와 변화를 검토한 결과, 골감소즈 환자에서는 정상 대조군에 비해 IGFBP-5가 감소하였는데 이 변화는 IGFBP-5의 분해효소가 작용하기 때문인 것으로 나타났다. IGFBP-5에 작용하는 단백질분해효소 저해제중 metallo계인 EDTA 및 1,10-phenanthroline과 seriner계인 aprotinin, heparin, heparin cofactor 2(HC2), heparine+HC2가 IGFBP-5에 대해 저해효과가 크므로 metalloprotease이면서 serine protease의 성질을 가지는 효소들이 IGFBP-5에 작용하였다. IGF-I과 IGF-II 그리고 insulin은 효소 활성에 아무런 영향이 없었다. IGFBP-5의 zymography에서 정상인과 골감소증 환제어서 180 kDa 크기의 band가 나타났고, gelatin zymography에서 정상 대조군의 경우 66 kDa과 97 kDa 정도의 band가 확인되었고 골감소증 환자의 경우는 69 kDa의 band가 확인되었다.

• BMB Reports
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• 제37권2호
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• pp.153-158
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• 2004

The acid-labile subunit (ALS) is known to interact with the IGF binding protein (IGFBP) in the presence of insulin-like growth factors (IGFs). Studies, however, indicate that ALS forms a doublet with IGFBP3, independent of IGFs. To characterize the structural domain required for the IGF-free ALS-IGFBP3 interaction, seven recombinant human IGFBP3 mutants were generated: three deletion mutants and four site-specific mutants that had altering N-terminal regions of IGFBP3. ALS and IGFBP3 mRNAs were co-injected into Xenopus oocytes, and their products were cross-linked and immunoprecipitated using antisera against ALS or IGFBP3. Among the deletion mutants, the mutant of D40 (deleted in 11-40th amino acids) exerted no effect in the interaction with ALS, while D60 (${\Delta}11$-60) demonstrated a moderate reduction. D88 (${\Delta}11$-88), however, showed a significant decrease. In the case of site-specific mutants, the mutation that alterated the IGF binding site (codons 56 or 80) exerted a significant reduction in the interaction, whereas codons 72 or 87 showed no significant change in the interaction with ALS. The stability of the ALS-IGFBP3 interaction was analyzed according to a time-dependent mode. Consistent with the binding study, mutants on the IGF binding sites (56 or 80) consistently show a weakness in the ALS-IGFBP3 interaction when compared to the mutants that covered the non-IGF binding sites (72 or 87). This study suggests that the N-terminal of IGFBP3, especially the IGF binding site, plays an important role in interacting with ALS as well as in stabilizing the dual complex, independent of IGFs.

• 약학회지
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• 제38권5호
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• pp.602-607
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• 1994

Based upon the previous experiments showing that kidney and lung tissues of rat had relatively abundant bradykinin binding sites, we tried to characterize and determine the densities of the bradykinin binding sites in the rabbit kidney tissue and proximal tubular cells under different growing conditions. Among the kidney tissue renal medulla segments showed the highest bradykinin binding sites. To determine which growth factors are to add in the serum free culture medium to express selectively the bradykinin binding sites in the rabbit kidney proximal tubular cells, we tried so called hormone-deletion approach and in here insulin, hydrocortisone, transferrin, triiodothyronine and prostaglandin $E_1$ are examined. By performing receptor binding assay and determination of protein concentrations, we may conclude that the most required hormones in the expression for bradykinin binding sites are insulin and transferrin, and fetal bovine serum is shown to be less effective in this regard.