Insulin-like growth factor binding protein 1 knockout increases free serum IGF-1 and enhances skeletal muscle mass and force in vivo

2015 ◽  
Vol 25 ◽  
pp. S218
Author(s):  
W. Eilers ◽  
P. Crossey ◽  
K. Foster
Keyword(s):  
Skeletal Muscle ◽  
Growth Factor ◽  
Muscle Mass ◽  
Skeletal Muscle Mass ◽  
Binding Protein ◽  
Insulin Like Growth Factor ◽  
Factor Binding ◽  
Free Serum

Tri-iodothyronine increases insulin-like growth factor binding protein-4 expression in rat hepatocytes

1997 ◽  
Vol 154 (1) ◽  
pp. 155-165 ◽  
Author(s):  
I Demori ◽  
C Bottazzi ◽  
A Voci ◽  
G Gallo ◽  
J-G Scharf ◽  
...  
Keyword(s):  
Growth Factor ◽  
Binding Protein ◽  
Mrna Level ◽  
Insulin Like Growth Factor ◽  
Cultured Hepatocytes ◽  
Adult Rats ◽  
Direct Role ◽  
Factor Binding ◽  
Rat Thyroid

Abstract Previous in vivo studies demonstrated significant variations in insulin-like growth factor binding protein-1 (IGFBP-1), IGFBP-2 and IGFBP-4 hepatic mRNAs and/or serum levels depending on the rat thyroid status. In this study we employed cultured hepatocytes from adult rats to demonstrate a possible direct regulation of these genes by tri-iodothyronine (T3). Northern blot analysis revealed that IGFBP-1 and -4 messages were clearly expressed, whereas IGFBP-2 signal was barely detectable. No significant effects on IGFBP-1 mRNA level or on peptide secretion were detected in T3-cultured hepatocytes. In contrast, significant increases in IGFBP-4 mRNA steady-state levels as well as in IGFBP-4 secretion were observed in hepatocytes cultured for 12–24 h in the presence of T3. The T3 effect on IGFBP-4 transcript levels appears to consist of enhanced gene transcription and is independent of ongoing protein synthesis. The T3-increased IGFBP-4 expression in cultured hepatocytes is consistent with our in vivo experiments demonstrating an increase in hepatic IGFBP-4 mRNA and serum IGFBP-4 levels in T3-treated rats. Furthermore, significant decreases in hepatic IGFBP-4 message and serum IGFBP-4 levels were observed in hypothyroid rats compared with euthyroid controls. Our data establish an important direct role for thyroid hormone in regulating IGFBP-4 expression and consequently IGF activity. Journal of Endocrinology (1997) 154, 155–165

scholarly journals Insulin-like growth factor 1 stimulates the angiogenic activity of adipose tissue–derived microvascular fragments

2019 ◽  
Vol 10 ◽  
pp. 204173141987983 ◽  
Author(s):  
Matthias W Laschke ◽  
Elena Kontaxi ◽  
Claudia Scheuer ◽  
Alexander Heß ◽  
Philipp Karschnia ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Growth Factor ◽  
Binding Protein ◽  
Insulin Like Growth Factor ◽  
Cellular Composition ◽  
Angiogenic Activity ◽  
Factor Binding ◽  
Factor Expression ◽  
Growth Factor Expression

Angiogenesis in adipose tissue is promoted by insulin-like growth factor 1 signaling. We analyzed whether this regulatory mechanism also improves the angiogenic activity of adipose tissue–derived microvascular fragments. Murine adipose tissue–derived microvascular fragments were cultivated for 24 h in the University of Wisconsin (UW) solution supplemented with vehicle, insulin-like growth factor 1, or a combination of insulin-like growth factor 1 and insulin-like growth factor–binding protein 4. Subsequently, we assessed their cellular composition, viability, proliferation, and growth factor expression. Moreover, cultivated adipose tissue–derived microvascular fragments were seeded onto collagen–glycosaminoglycan scaffolds, which were implanted into dorsal skinfold chambers to study their vascularization and incorporation. Insulin-like growth factor 1 increased the viability and growth factor expression of adipose tissue–derived microvascular fragments without affecting their cellular composition and proliferation. Accordingly, scaffolds containing insulin-like growth factor 1–stimulated adipose tissue–derived microvascular fragments exhibited an enhanced in vivo vascularization and incorporation. These positive insulin-like growth factor 1 effects were reversed by additional exposure of adipose tissue–derived microvascular fragments to insulin-like growth factor–binding protein 4. Our findings indicate that insulin-like growth factor 1 stimulation of adipose tissue–derived microvascular fragments is suitable to improve their vascularization capacity.

scholarly journals Factors regulating the rat insulin-like growth factor-binding protein-1 response to octreotide

1998 ◽  
Vol 158 (1) ◽  
pp. 61-68
Author(s):  
MS Lewitt ◽  
D Cameron-Smith ◽  
NM Clarke ◽  
H Saunders ◽  
JL Phuyal
Keyword(s):  
Growth Factor ◽  
Time Course ◽  
Binding Protein ◽  
Similar Response ◽  
Insulin Like Growth Factor ◽  
High Fat ◽  
Short Term ◽  
Factor Binding ◽  
The Mean

Insulin-like growth factor-binding protein-1 (IGFBP-1) production is increased by somatostatin and its analogues. In order to determine the time course and identify possible mechanisms of this increase in vivo we administered octreotide to rats and determined IGFBP-1 concentrations by RIA. After 60 min of anaesthesia, the mean baseline IGFBP-1 concentrations were 166 (95% confidence interval 123 to 225) ng/ml and increased in saline-infused animals to 729 (488 to 1086) ng/ml after 180 min. IGFBP-1 was stimulated transiently in response to octreotide, with circulating IGFBP-1 concentrations peaking at 1605 (1220 to 2111) ng/ml at 105 min during a continuous infusion of octreotide (100 micrograms/kg per h). In conscious chronically cannulated rats, baseline IGFBP-1 concentrations were 22 (18 to 28) ng/ml, 8-fold less than in the anaesthetised state, and were stimulated in the short term after administration of an octreotide bolus (100 micrograms/kg s.c.) to reach 88 (62 to 126) ng/ml at 60 min. A similar response was seen after i.v. administration to conscious rats. Intravenous bolus of octreotide (100 micrograms/kg) in rats anaesthetised for 3 h resulted in an increase in IGFBP-1 to peak at 1556 (1268 to 1910) ng/ml at 60 min. The IGFBP-1 response to octreotide was diminished in high-fat fed hyperinsulinaemic rats. The pattern of disappearance of iodinated IGFBP-1 from the circulation was not influenced by octreotide. The changes in GH, insulin and glucose concentrations alone did not sufficiently account for the patterns of response observed. We conclude that, in rats, octreotide stimulates IGFBP-1 acutely and this response is potentiated by factors related to anaesthesia.

scholarly journals IMP2 Increases Mouse Skeletal Muscle Mass and Voluntary Activity by Enhancing Autocrine Insulin-Like Growth Factor 2 Production and Optimizing Muscle Metabolism

2019 ◽  
Vol 39 (7) ◽  
Author(s):  
Laura Regué ◽  
Fei Ji ◽  
Daniel Flicker ◽  
Dana Kramer ◽  
William Pierce ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Oxygen Consumption ◽  
Growth Factor ◽  
Muscle Mass ◽  
Skeletal Muscle Mass ◽  
Wheel Running ◽  
Muscle Metabolism ◽  
Insulin Like Growth Factor ◽  
Voluntary Activity ◽  
Mouse Muscle

ABSTRACT Insulin-like growth factor 2 (IGF2) mRNA binding protein 2 (IMP2) was selectively deleted from adult mouse muscle; two phenotypes were observed: decreased accrual of skeletal muscle mass after weaning and reduced wheel-running activity but normal forced treadmill performance. Reduced wheel running occurs when mice are fed a high-fat diet but is normalized when mice consume standard chow. The two phenotypes are due to altered output from different IMP2 client mRNAs. The reduced fiber size of IMP2-deficient muscle is attributable, in part, to diminished autocrine Igf2 production; basal tyrosine phosphorylation of the insulin and IGF1 receptors is diminished, and Akt1 activation is selectively reduced. Gsk3α is disinhibited, and S536-phosphorylated ε subunit of eukaryotic initiation factor 2B [eIF2Bε(S536)] is hyperphosphorylated. Protein synthesis is reduced despite unaltered mTOR complex 1 activity. The diet-dependent reduction in voluntary exercise is likely due to altered muscle metabolism, as contractile function is normal. IMP2-deficient muscle exhibits reduced fatty acid oxidation, due to a reduced abundance of mRNA of peroxisome proliferator-activated receptor α (PPARα), an IMP2 client, and PPARα protein. IMP2-deficient muscle fibers treated with a mitochondrial uncoupler to increase electron flux, as occurs with exercise, exhibit reduced oxygen consumption from fatty acids, with higher oxygen consumption from glucose. The greater dependence on muscle glucose metabolism during increased oxygen demand may promote central fatigue and thereby diminish voluntary activity.

Insulin‐like growth factor binding protein 2 (IGFBP‐2) separates hypertrophic and hyperplastic effects of growth hormone (GH)/IGF‐I excess on adrenocortical cells in vivo

2002 ◽  
Vol 16 (13) ◽  
pp. 1721-1731 ◽  
Author(s):  
Andreas Hoeflich ◽  
Matthias M. Weber ◽  
Thomas Fisch ◽  
Sabine Nedbal ◽  
Christian Fottner ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Growth Factor ◽  
Binding Protein ◽  
Insulin Like Growth Factor ◽  
Adrenocortical Cells ◽  
Factor Binding ◽  
Igf I
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