IGF

IGF or Insulin-like growth factor is a hormone that has a similar molecular structure to insulin. It plays an important role in childhood growth and continues to have anabolic effects in adults. There are two types of IGF: IGF-1 and IGF-2.

Function

IGF is produced by the liver as an endocrine hormone as well as by target tissues in a paracrine/autocrine fashion. Production is stimulated by growth hormone (GH) and can be retarded by undernutrition, hypothyroidism or declines in GH or insulin levels.

IGF-1 is primarily responsible for the long bone growth in children and it also affects muscle growth and repair of adults. IGF-2 is a major fetal growth factor in contrast to IGF-1 which is both a fetal and postnatal growth factor.

Role in disease

IGF-1 has been reported to be high in people with acromegaly due to an excess of growth hormone. In contrast, low levels of IGF-1 are seen in growth hormone deficiency. It has also been reported that people with cancer, particularly men with prostate cancer, have elevated levels of IGF-1.

Clinical significance

IGF-1 may be measured in the blood in order to determine the production of GH, as GH secretion cannot be measured directly because it is released in pulses. IGF-1 may also be used in the treatment of short stature and in growth hormone therapy.

See also

• Growth hormone
• Acromegaly
• Prostate cancer

References

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