Insulin-like growth factor 1

A protein involved in growth and development

Diagram of IGF-1 structure

Insulin-like Growth Factor 1 (IGF-1) is a protein that in humans is encoded by the IGF1 gene. It is a hormone similar in molecular structure to insulin. IGF-1 plays an important role in childhood growth and continues to have anabolic effects in adults.

Structure

IGF-1 is a small protein with a molecular weight of approximately 7,649 daltons. It consists of 70 amino acids in a single chain with three intramolecular disulfide bridges. The structure of IGF-1 is similar to that of insulin, which is why it is referred to as "insulin-like."

Function

IGF-1 is primarily produced in the liver as an endocrine hormone and is also produced in target tissues in a paracrine/autocrine fashion. It is a major mediator of the effects of growth hormone (GH). Growth hormone is made in the pituitary gland, released into the bloodstream, and 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, nerve, skin, and lung cells.

Mechanism of Action

IGF-1 exerts its effects by binding to the IGF-1 receptor (IGF1R), which is a receptor tyrosine kinase. Upon binding, IGF-1 activates the receptor, leading to the activation of intracellular signaling pathways such as the PI3K/AKT pathway and the MAPK/ERK pathway. These pathways promote cell growth, proliferation, and survival.

Clinical Significance

IGF-1 levels are important in the diagnosis and management of growth disorders. Low levels of IGF-1 can indicate growth hormone deficiency, while high levels can be associated with conditions such as acromegaly and gigantism. IGF-1 is also being studied for its potential role in aging, cancer, and metabolic disorders.

Therapeutic Use

Recombinant IGF-1 is used in the treatment of growth failure in children with severe primary IGF-1 deficiency or with growth hormone gene deletion who have developed neutralizing antibodies to growth hormone.

Related pages

• Insulin-like growth factor 2
• Growth hormone
• IGF-1 receptor
• Endocrinology