title: Insulin-like growth factor-I (IGF-I) and clinical nutrition.
abstract: IGF-I (insulin-like growth factor-I) is a peptide hormone, produced predominantly by the liver in response to pituitary GH (growth hormone), which is involved in a wide variety of physiological processes. It acts in an endocrine, paracrine and autocrine manner to promote growth. The production of IGF-I signals the availability of nutrients needed for its anabolic actions. Recently, there has been growing interest in its role in health and disease. IGF-I has long been known to be regulated by nutrition and dysregulated in states of under- and over-nutrition, its serum concentrations falling in malnutrition and responding promptly to refeeding. This has led to interest in its utility as a nutritional biomarker. A considerable evidence base supports utility for measurement of IGF-I in nutritional contexts. Its concentration may be valuable in providing information on nutritional status, prognosis and in monitoring nutritional support. However, it is insufficiently specific for use as a screening test for under nutrition as its serum concentration is influenced by many factors other than nutritional status, notably the APR (acute-phase response) and endocrine conditions. Concentrations should be interpreted along with clinical findings and the results of other investigations such as CRP (C-reactive protein). More recently, there has been interest in free IGF-I which holds promise as a nutritional marker. The present review covers nutritional regulation of IGF-I and its dysregulation in disease, then goes on to review recent studies supporting its utility as a nutritional marker in clinical contexts. Although not currently recommended by clinical guidelines, it is likely that, in time, measurement of IGF-I will become a routine part of nutritional assessment in a number of these contexts.
authors.affiliation: Peptide Hormones Supraregional Assay Service, Clinical Biochemistry Department, Royal Surrey County Hospital NHS Foundation Trust, Guildford, Surrey, UK. callum.livingstone@nhs.net
authors.forename: Callum
authors.initials: C
authors.lastname: Livingstone
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000235:genetics / Q000378:metabolism*; D015596:Nutrition Assessment; D009748:Nutrition Disorders / Q000097:blood* / Q000175:diagnosis / Q000235:genetics / Q000503:physiopathology / Q000628:therapy; D009752:Nutritional Status; D018529:Nutritional Support; D011379:Prognosis
chemical_list: D015415:Biomarkers; D007334:Insulin-Like Growth Factor I