Insulin-like growth factor ii

Insulin-like Growth Factor II (IGF-II) is a protein hormone that plays a crucial role in cell growth, development, and metabolism in the human body. It is part of a larger family of insulin-like growth factors that are involved in the development and growth of tissues. IGF-II is particularly significant during fetal development, where it contributes to the growth and differentiation of tissues and organs.

Structure and Function

IGF-II is a single-chain polypeptide that shares structural similarities with insulin and Insulin-like Growth Factor I (IGF-I). It binds to the insulin-like growth factor 1 receptor (IGF1R) and the insulin receptor (IR), activating pathways that lead to DNA synthesis and cell proliferation. IGF-II also binds to the insulin-like growth factor 2 receptor (IGF2R), which plays a role in the regulation of its bioavailability and activity.

The expression of IGF-II is highly regulated by genomic imprinting, a process that results in the gene being expressed only from the allele inherited from a specific parent. In the case of IGF-II, it is typically expressed from the paternal allele.

Role in Development and Disease

During fetal development, IGF-II is critical for the growth and differentiation of many types of tissues. It has been shown to be essential for placenta development and function, as well as for the growth of the fetus itself.

Abnormalities in IGF-II expression or function have been implicated in various diseases and conditions. Overexpression of IGF-II has been associated with Beckwith-Wiedemann syndrome, a growth disorder characterized by an increased risk of childhood tumors and other abnormalities. Conversely, reduced levels of IGF-II have been linked to growth retardation and developmental delays.

In adults, altered levels of IGF-II have been associated with cancer, metabolic syndrome, and type 2 diabetes. The role of IGF-II in cancer is particularly complex, as it can promote tumor growth and survival through its effects on cell proliferation and apoptosis.

Research and Therapeutic Potential

Given its role in cell growth and metabolism, IGF-II is a subject of ongoing research, particularly in the context of cancer therapy and regenerative medicine. Strategies to modulate IGF-II activity are being explored as potential treatments for diseases characterized by abnormal cell growth, such as cancer and fibrosis.

Conclusion

IGF-II is a vital hormone that plays a key role in the growth and development of tissues in the human body. Its functions extend from fetal development to adult physiology, influencing health and disease. Understanding the mechanisms of IGF-II action and regulation offers potential pathways for therapeutic intervention in a range of conditions.