Changes induced by non-enzymatic glycosylation of IGF-binding protein-3: effects on its binding properties and on its modulatory effect on IGF-I mitogenic action

1995 ◽  
Vol 144 (1) ◽  
pp. 119-126 ◽  
Author(s):  
A M Cortizo ◽  
J J Gagliardino
Keyword(s):  
Binding Protein ◽  
Mitogenic Activity ◽  
Dependent Manner ◽  
Binding Properties ◽  
Igf I ◽  
Igf Binding ◽  
Igf Binding Protein ◽  
Enzymatic Glycosylation ◽  
Igfbp 3

Abstract The aim of this study was to demonstrate the feasibility of in vitro non-enzymatic glycosylation of IGF-binding protein-3 (IGFBP-3) and whether this process affects its binding properties and its modulatory effect on IGF-I mitogenic activity. Swiss 3T3 fibroblasts were cultured and the IGFBP-3 released into the medium (CM) glycated with either labelled or unlabelled glucose. Parallel glycation studies were performed using standard human IGFBP-3. Both species of IGFBP-3 became effectively glycated in a dose-dependent manner. Glycated IGFBP-3 bound larger amounts of 125I-labelled IGF-I than its non-glycated form. According to Scatchard analysis this effect might be due to an increase in the number of binding sites of the IGFBP-3 molecule rather than to changes in its affinity constants, which remain unchanged. Preincubation of fibroblasts with CM containing IGFBP-3 for 16 h before the addition of IGF-I enhanced the stimulatory effect of the hormone on thymidine incorporation into cell DNA. This potentiation was blunted when in vitro glycated instead of non-glycated IGFBP-3 was employed. These results provide further evidence of the in vitro glycation of IGFBP-3 and demonstrate that this process affects both its binding properties and its enhancing effect on IGF-I mitogenic activity. These changes may explain, at least partially, the development of many alterations observed in poorly controlled diabetic patients. Journal of Endocrinology (1995) 144, 119–126

scholarly journals Effect of recombinant porcine IGF-binding protein-3 on proliferation of embryonic porcine myogenic cell cultures in the presence and absence of IGF-I

2003 ◽  
Vol 176 (2) ◽  
pp. 227-235 ◽  
Author(s):  
MS Pampusch ◽  
E Kamanga-Sollo ◽  
ME White ◽  
MR Hathaway ◽  
WR Dayton
Keyword(s):  
Cell Proliferation ◽  
Muscle Development ◽  
Binding Protein ◽  
Myogenic Cell ◽  
Complete Suppression ◽  
Dependent Manner ◽  
Igf I ◽  
Igf Binding ◽  
Igf Binding Protein ◽  
Igfbp 3

IGF-binding protein (IGFBP)-3 is produced by cultured porcine embryonic myogenic cell (PEMC) cultures and is secreted into the medium. Levels of secreted IGFBP-3 and IGFBP-3 mRNA are significantly reduced during differentiation and increase after differentiation is complete, suggesting that IGFBP-3 may play some role in myogenesis and/or in changes in myogenic cell proliferation that accompany differentiation. IGFBP-3 reportedly may either suppress or stimulate proliferation of cultured cells depending on cell type. Additionally, IGFBP-3 has been shown to affect proliferation via both IGF-dependent and IGF-independent mechanisms in some cell types but not all. Currently, the effect, if any, of IGFBP-3 on myogenic cell proliferation is not known. Consequently, the goal of this study was to assess the IGF-I-dependent and IGF-I-independent actions of recombinant porcine IGFBP-3 on proliferation of cultured porcine myogenic cells. To facilitate these investigations, we have expressed porcine IGFBP-3 in the baculovirus system, purified and characterized the expressed recombinant porcine IGFBP-3 (rpIGFBP-3), and produced and characterized an anti-porcine IGFBP-3 antibody that neutralizes the biological activity of porcine IGFBP-3. rpIGFBP-3 suppressed IGF-I-stimulated proliferation of PEMCs in a concentration-dependent manner with equimolar concentrations of IGF-I and rpIGFBP-3, resulting in complete suppression of IGF-I-stimulated proliferation. rpIGFBP-3 also suppressed Long-R3-IGF-I-stimulated proliferation of PEMC, indicating that rpIGFBP-3 possesses IGF-independent activity in this cell system. These data have established that IGFBP-3 has the potential to affect proliferation of PEMCs during critical periods of muscle development that may impact ultimate muscle mass achievable postnatally.

Specimen processing time and measurement of total insulin-like growth factor-I (IGF-I), free IGF-I, and IGF binding protein-3 (IGFBP-3)

2006 ◽  
Vol 16 (2) ◽  
pp. 86-92 ◽  
Author(s):  
Tiffany G. Harris ◽  
Howard D. Strickler ◽  
Herbert Yu ◽  
Michael N. Pollak ◽  
E. Scott Monrad ◽  
...  
Keyword(s):  
Growth Factor ◽  
Processing Time ◽  
Binding Protein ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Igf I ◽  
Specimen Processing ◽  
Igf Binding ◽  
Igf Binding Protein ◽  
Igfbp 3

scholarly journals Genetic Determinants of Circulating Insulin-Like Growth Factor (IGF)-I, IGF Binding Protein (BP)-1, and IGFBP-3 Levels in a Multiethnic Population

2007 ◽  
Vol 92 (9) ◽  
pp. 3660-3666 ◽  
Author(s):  
Iona Cheng ◽  
Katherine DeLellis Henderson ◽  
Christopher A. Haiman ◽  
Laurence N. Kolonel ◽  
Brian E. Henderson ◽  
...  
Keyword(s):  
Growth Factor ◽  
Binding Protein ◽  
Insulin Like Growth Factor ◽  
Genetic Determinants ◽  
Igf I ◽  
Igf Binding ◽  
Multiethnic Population ◽  
Igf Binding Protein ◽  
Igfbp 3

Moderate food restriction reduces serum IGF-I and alters circulating IGF-binding protein profiles in lactating rats

1997 ◽  
Vol 152 (2) ◽  
pp. 303-316 ◽  
Author(s):  
M H Monaco ◽  
S M Donovan
Keyword(s):  
Body Weight ◽  
Mammary Gland ◽  
Food Restriction ◽  
Binding Protein ◽  
Igf I ◽  
Pregnancy And Lactation ◽  
Igf Binding ◽  
Igf Binding Protein ◽  
Serum Gh ◽  
Igfbp 3

Abstract The role of somatogenic and lactogenic hormones in the adaptative mechanisms which occur in response to nutrient restriction during lactation is unknown. To characterize the effect of food restriction during lactation on serum IGF-I, GH and prolactin concentrations and serum IGF-binding protein (IGFBP) profiles, lactating dams had free access to food (control) or were restricted to 60% of control intake during pregnancy and lactation (RPL) or only during lactation (RL). Serum, milk and mammary gland samples were collected throughout lactation. RL dams lost body weight, control dams gained weight, while RPL dams maintained body weight during lactation. By day 20, body and mammary gland weights of RL and RPL dams did not differ and were lower than control (P<0·05). Serum IGF-I concentrations in restricted groups were lower than control (P<0·05), however, hepatic expression of IGF-I mRNA did not differ between groups in early (day 1) or mid-lactation (day 8) and was increased on day 20 in RL dams compared with RPL or control. These data suggest that serum IGF-I and hepatic IGF-I mRNA expression are not co-ordinately regulated in the food-restricted lactating rat. In early lactation, serum IGFBP-3 was lower in RPL dams than control (P<0·05), whereas IGFBP-1 and -2 were increased in RL and RPL dams in late lactation compared with control. The decrease in IGFBP-3 and increase in lower molecular weight IGFBP may have contributed to the reduction in serum IGF-I by increasing IGF-I clearance from the circulation. Serum GH and prolactin were measured in samples obtained between 0900 and 1200 h. Serum GH did not differ with the exception of an increase on day 1 in control relative to RPL dams and on day 20 in RL dams relative to RPL and control. Serum prolactin was higher in the RL dams than controls on day 4. In summary, food restriction during pregnancy and lactation or solely during lactation results in similar reductions in serum IGF-I and alterations in serum IGFBP despite differences in body weight responses to food restriction during lactation. Journal of Endocrinology (1997) 152, 303–316

Major secretory protein of human decidualized endometrium in pregnancy is an insulin-like growth factor-binding protein

1988 ◽  
Vol 118 (2) ◽  
pp. 317-328 ◽  
Author(s):  
S. C. Bell ◽  
S. R. Patel ◽  
J. A. Jackson ◽  
G. T. Waites
Keyword(s):  
Growth Factor ◽  
Amniotic Fluid ◽  
Incubation Medium ◽  
Binding Protein ◽  
Secretory Protein ◽  
Insulin Like Growth Factor ◽  
Igf I ◽  
Igf Binding ◽  
Igf Binding Protein

ABSTRACT Pregnancy-associated endometrial α1-globulin (α1-PEG) is quantitatively the major secretory protein product, synthesized and secreted in vitro, of the human decidualized endometrium during pregnancy. This protein has been purified from cytosolic extracts of this tissue and has now been characterized as a 32 kDa somatomedin/insulin-like growth factor (IGF)-binding protein. Immunoreactive α1-PEG isolated from amniotic fluid exhibited identical physiochemical properties and IGF-I-binding characteristics. In cytosolic extracts of pregnancy endometrium, in incubation medium of this tissue and in amniotic fluid, the 32 kDa protein represented the major α1-PEG immunoreactive protein and major IGF-I-binding component. Purified α1-PEG and incubation medium of pregnancy endometrium competed for IGF-I with placental membrane IGF receptors in vitro. The implications of the endometrial source of IGF-I-binding protein are dicussed with reference to the origin of the amniotic fluid and serum small Mr IGF-binding protein and to the suggested paracrine effect upon trophoblast proliferation. J. Endocr. (1988) 118, 317–328

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