|Products||IGF-I IRMA Test (Non-Extraction)|
|Company||Diagnostic Systems Laboratories, Inc.|
|Item||IGF-I IRMA Test (Non-Extraction)|
|Description|| Insulin-like growth factor I (IGF-I or somatomedin C) is a 7.6 kDa peptide produced primarily in the liver. It acts as a potent mitogen of cellular proliferation, exerting its actions by binding to specific cell-surface receptors. In the circulation, IGF-I is bound to IGF-binding proteins (IGFBPs), which appear to regulate the actions of IGF-I by modulating the interaction of IGF-I with the Type 1 IGF receptor. The majority of IGF-I in blood is bound to a high molecular weight ternary complex with IGFBP-3 and ALS [1,2]. A smaller proportion of IGF-I circulates in association with other IGFBPs , and less than 5% is unbound or free IGF-I. It is believed that free IGF-I represents the biologically active fraction of IGF-I .
IGF-I concentrations in serum are dependent on age and sex. Levels increase from birth through mid-puberty, then decline to relatively stable levels during adult life, with a modest decrease in elderly people. In addition, IGF-I levels remain relatively stable throughout the day [4,5]. IGF-I is also dependent on growth hormone (GH) secretion, with IGF-I mediating many of the actions of GH . In GH deficiency, malnutrition  and GH-receptor deficiency , serum IGF-I levels are low. Conversely, in acromegaly (GH excess) serum IGF-I levels are elevated [4,6]. Measurement of IGF-I levels in serum is a useful diagnostic test for the clinical evaluation of GH-related disorders. Additionally, there is a growing research interest in the role of IGF-I in cancer risk assessment [8.9].
|Info|| Diagnostic Systems Laboratories, Inc.|
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