Synthesized by liver cells.
Insulin-like growth factor 1
Insulin-like growth factor 1 (IGF-1), also called somatomedin C.
A hormone similar in molecular structure to insulin.
Has an important role in childhood growth and continues to have anabolic effects in adults.
IGF-1 is a peptide and neurotrophic factor that mediates some of the effects of growth hormone.
IGF-1 elicits its physiological effects by binding to a specific receptor tyrosine kinase, the IGF-1 receptor, to control tissue growth and remodeling.
In the brain, IGF-1 functions as a neurotrophic factor that, like BDNF, plays a significant role in cognition, neurogenesis, and neuronal survival.
Physical activity is associated with increased levels of IGF-1 in blood serum, which is known to contribute to neuroplasticity in the brain due to its capacity to cross the blood–brain barrier and blood–cerebrospinal fluid barrier.
A polypeptide that has mitogenic and anti-apoptotic effects.
A protein that in humans is encoded by the IGF1 gene, on chromosome 12
Band 12q23.2
The liver is the principal site of IGF-1 production.
IGF-1 has growth-stimulating effects on a wide variety of tissues.
IGF-1 is bound to IGF binding proteins at approximately 99%.
IGF-1 is also generated within target tissues.
It is both an endocrine and an autocrine/paracrine hormone.
It has stimulatory effects on osteoblast and chondrocyte activity to promote bone growth.
Its molecular functions include :
hormone activity
insulin receptor binding
growth factor activity
Integrin binding
protein binding
insulin-like growth factor receptor binding
Biological process of positively regulatng the transcription region of DNA binding.
skeletal system development
positive regulation of glucose import
movement of cell or subcellular component
muscle organ development
positive regulation of Ras protein signal transduction
response to heat
positive regulation of cardiac muscle hypertrophy
positive regulation of smooth muscle cell migration
DNA replication
positive regulation of insulin-like growth factor receptor signaling pathway
phosphatidylinositol 3-kinase signaling
positive regulation of DNA binding
Ras protein signal transduction
cell proliferation
positive regulation of mitotic nuclear division
positive regulation of trophectodermal cell proliferation
positive regulation of glycogen biosynthetic process
positive regulation of protein import into nucleus, translocation
positive regulation of fibroblast proliferation
ERK1 and ERK2 cascade
negative regulation of extrinsic apoptotic signaling pathway
cell activation
negative regulation of oocyte development
positive regulation of transcription, DNA-templated
bone mineralization
regulation of peptidyl-tyrosine phosphorylation
regulation of MAPK cascade
proteoglycan biosynthetic process
regulation of activated T cell proliferation
regulation of epithelial cell proliferation
negative regulation of release of cytochrome c from mitochondria
protein stabilization
myotube cell development
positive regulation of DNA replication
myoblast proliferation
skeletal muscle satellite cell maintenance involved in skeletal muscle regeneration
positive regulation of protein secretion
positive regulation of glycoprotein biosynthetic process
regulation of gene expression
phosphatidylinositol-mediated signaling
positive regulation of smooth muscle cell proliferation
cellular protein metabolic process
muscle hypertrophy
protein kinase B signaling
positive regulation of cell migration
platelet degranulation
positive regulation of phosphatidylinositol 3-kinase signaling
myoblast differentiation
glycolate metabolic process
positive regulation of glycolytic process
negative regulation of smooth muscle cell apoptotic process
signal transduction
positive regulation of transcription from RNA polymerase II promoter
positive regulation of cell growth involved in cardiac muscle cell development
activation of MAPK activity
positive regulation of cell proliferation
positive regulation of osteoblast differentiation
activation of protein kinase B activity
insulin-like growth factor receptor signaling pathway
negative regulation of apoptotic process
positive regulation of tyrosine phosphorylation of STAT protein
It is produced primarily by the liver as an endocrine hormone as well as in target tissues in a paracrine/autocrine fashion.
Production is stimulated by growth hormone (GH) and can be slowed by undernutrition, growth hormone insensitivity, lack of growth hormone receptors, or failures of the downstream signaling pathway.
Approximately 98% of IGF-1 is always bound to one of 6 binding proteins.
It is produced throughout life.
Its highest rate of production occurs during the pubertal growth spurt. with its lowest levels occur in infancy and old age.
Levels vary by: insulin levels, time of day, age, gender, exercise stress level, nutritional status, BMI, comorbid illnesses, ethnicity, and hormonal status.
It is a primary mediator of the effects of growth hormone.
Growth hormone is produced in the anterior pituitary gland, is released into the blood stream, and then stimulates the liver to produce IGF-1.
IGF-1 then stimulates systemic body growth, and has growth-promoting effects on almost every cell in the body, especially skeletal muscle, cartilage, bone, liver, kidney, nerves, skin, hematopoietic cell, and lungs.
Has insulin-like effects, and can also regulate cell growth and development, especially in nerve cells, as well as cellular DNA synthesis.
Its major action is mediated by binding to its specific receptor, the insulin-like growth factor 1 receptor (IGF1R).
The insulin-like growth factor 1 receptor is present on many cell types in many tissues.
When binding to the IGF1R, a receptor tyrosine kinase, initiates intracellular signaling; IGF-.
IGF-1 is one of the most potent natural activators of the AKT signaling pathway, a stimulator of cell growth and proliferation, and a potent inhibitor of programmed cell death.
IGF-1 binds to at least two cell surface receptors: the IGF-1 receptor (IGF1R), and the insulin receptor.
The IGF-1 receptor binds IGF-1 at significantly higher affinity than the IGF-1 that is bound to the insulin receptor.
The IGF-1 receptor is a receptor tyrosine kinase – meaning it signals by causing the addition of a phosphate molecule on particular tyrosines.
IGF-1 activates the insulin receptor at approximately 0.1 times the potency of insulin.
Insulin-like growth factor 1 receptor and other tyrosine kinase growth factor receptors signal through multiple pathways: phosphatidylinositol-3 kinase (PI3K) and its downstream partner, the mammalian target of rapamycin (mTOR).
Diseases characterized by inability to make or respond to IGF-1 produce a distinctive type of dwarfism, Laron syndrome.
With Laron syndrome patients do not respond to growth hormone treatment due to a lack of GH receptors.
Patients with Laron syndrome have strikingly low rates of cancer and diabetes.