Receptor binding of insulin-like growth factor-I to mammary microsomes from non-pregnant, pregnant and lactating sheep

1993 ◽  
Vol 136 (2) ◽  
pp. 297-304 ◽  
Author(s):  
S. J. Winder ◽  
S. D. Wheatley ◽  
I. A. Forsyth
Keyword(s):  
Growth Factor ◽  
Membrane Protein ◽  
Binding Affinity ◽  
Binding Sites ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Pregnant Sheep ◽  
Igf I ◽  
Igf Receptor

ABSTRACT Sucrose density centrifugation was used to prepare a partially purified membrane fraction from the mammary glands of non-pregnant, pregnant and lactating sheep. The binding of125 I-labelled insulin-like growth factor-I (IGF-I) was dependent on membrane protein concentration, pH, time and temperature. The binding showed the characteristics of a type-1 IGF receptor, being displaced by IGF-I (median effective dose (ED50) 0·55 nmol/l), less effectively by IGF-II (ED50 8·8 nmol/l) and least effectively by insulin. Glucagon, ovine prolactin and ovine placental lactogen could not displace binding. A molecular weight of 135 000 was determined by affinity cross-linking using disuccinimidyl suberate; this was consistent with the reported size of the type-1 receptor α-subunit. Scatchard analysis was used to determine binding affinity and numbers of IGF-I-binding sites. A single class of high-affinity binding sites was found in all physiological states. In non-pregnant sheep and sheep at days 40, 75 and 110–120 of pregnancy and at term, the binding affinity was similar (apparent dissociation constant (Kd) 2·73 ±0·31 nmol/l, n = 22). In lactating sheep (weeks 1, 4 and 10), the binding affinity was significantly (P = 0·02) higher (Kd 0·77± 0·06 nmol/l n = 9). Binding capacity was similar in non-pregnant and pregnant sheep (1005 ± 113 fmol/mg, n = 19), but fell by parturition and remained low in lactation (570±52 fmol/mg membrane protein, n = 12). The results suggest that the mammary growth of pregnancy is not regulated at the level of the type-1 IGF receptor. Journal of Endocrinology (1993) 136, 297–304

scholarly journals The C Region of Human Insulin-like Growth Factor (IGF) I Is Required for High Affinity Binding to the Type 1 IGF Receptor

1989 ◽  
Vol 264 (19) ◽  
pp. 11004-11008 ◽  
Author(s):  
M L Bayne ◽  
J Applebaum ◽  
D Underwood ◽  
G G Chicchi ◽  
B G Green ◽  
...  
Keyword(s):  
Growth Factor ◽  
Human Insulin ◽  
Affinity Binding ◽  
Insulin Like Growth Factor ◽  
High Affinity Binding ◽  
High Affinity ◽  
Igf I ◽  
Igf Receptor

scholarly journals Insulin-like growth factor (IGF) receptor, IGF-I, interleukin-1 beta (IL-1 beta), and IL-6 mRNA expression in osteoarthritic and normal human cartilage.

1996 ◽  
Vol 44 (2) ◽  
pp. 133-141 ◽  
Author(s):  
J Middleton ◽  
A Manthey ◽  
J Tyler
Keyword(s):  
Extracellular Matrix ◽  
Growth Factor ◽  
Interleukin 1 ◽  
Insulin Like Growth Factor ◽  
Interleukin 1 Beta ◽  
Normal Cartilage ◽  
Igf I ◽  
Cartilage Cells ◽  
Igf Receptor

Insulin-like growth factor-I (IGF-I) stimulates the production of extracellular matrix by cartilage cells and this action is mediated through the Type 1 IGF receptor. Expression of the genes for the IGF receptor and for IGF-I was examined in normal and osteoarthritic (OA) human articular cartilage by in situ hybridization. RNA transcripts for Type 1 receptor were detected in all 73 tissue samples and in 80-100% of chondrocytes per section. Signal for the receptor was present in normal and OA cells, and the highest message levels were in the tissues exhibiting advanced pathology. Strong message signals in the cells of the more advanced lesions were also noted for IGF-I, whereas little or no IGF-I mRNA was detected in normal samples. Interleukin-1 beta (IL-1 beta) induces degradation of extracellular matrix by cartilage cells, and expression of this gene was examined with digoxygenin-labeled oligonucleotide probes. mRNA transcripts were detected in only one in five of the cartilage samples taken from OA joints. Unlike IGF-I, expression did not correlate with the degree of OA pathology and positive cells were demonstrated also in samples from young normal cartilage. IL-6 mRNA was present both in surface and deep cells of fibrillated OA cartilage, but no signal was evident in histologically normal cartilage from OA tissue or in normal young joints.

Localization of binding sites for insulin-like growth factor-I (IGF-I) in the rat brain by quantitative autoradiography

1988 ◽  
Vol 444 (2) ◽  
pp. 205-213 ◽  
Author(s):  
Nancy J. Bohannon ◽  
Eric S. Corp ◽  
Barbara J. Wilcox ◽  
Dianne P. Figlewicz ◽  
Daniel M. Dorsa ◽  
...  
Keyword(s):  
Growth Factor ◽  
Rat Brain ◽  
Binding Sites ◽  
Quantitative Autoradiography ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Igf I ◽  
Growth Factor I

Characteristics of binding of insulin-like growth factor (IGF)-I and IGF-II analogues to the type 1 IGF receptor determined by BIAcore analysis

2002 ◽  
Vol 269 (3) ◽  
pp. 961-968 ◽  
Author(s):  
Briony E. Forbes ◽  
Perry J. Hartfield ◽  
Kerrie A. McNeil ◽  
Kathy H. Surinya ◽  
Steven J. Milner ◽  
...  
Keyword(s):  
Growth Factor ◽  
Insulin Like Growth Factor ◽  
Igf I ◽  
Igf Receptor

Insulin-like growth factor-I and its association with binding proteins in bovine milk

1989 ◽  
Vol 120 (1) ◽  
pp. 21-29 ◽  
Author(s):  
P. G. Campbell ◽  
C. R. Baumrucker
Keyword(s):  
Growth Factor ◽  
Binding Sites ◽  
Acid Treatment ◽  
Binding Protein ◽  
Bovine Milk ◽  
Immunoreactive Insulin ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Igf I ◽  
Growth Factor I

ABSTRACT Immunoreactive insulin-like growth factor-I (IGF-I) in bovine milk was quantified. IGF-I was principally association with an ∼45 kDa binding protein. In addition, a small fraction of IGF-I occurred at a molecular weight approximately the same as that of unbound IGF-I. Available binding sites existed on the ∼45 kDa binding protein. Bound IGF-I was readily dissociated from binding protein by acid treatment. When IGF-I was estimated in milk obtained from primiparous and multiparous cows, multiparous cows had a higher concentration (40 μmol/l) at parturition than primiparous cows (19·2 μmol/l). By day 2 of lactation, IGF-I concentrations were 30 and 50% of initial estimates for multiparous and primiparous cows respectively. The final IGF-I concentration, on day 56 of lactation, was 4·5 μmol/l for combined parity groups. At parturition in multiparous cows, the mass of IGF-I was estimated at 183 and 157 μmol for blood and milk pools respectively. Milk, therefore, represents a substantial pool of IGF-I in the cow. The mechanism of the appearance of IGF-I in bovine milk is unknown. Journal of Endocrinology (1989) 120, 21–29

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