Free insulin-like growth factor I: are we hunting a ghost?
During the last decade, there has been an increasing number of publications reporting concentrations of free dissociable insulin-like growth factor I (IGF-I) in serum or plasma. The goal for attempting to measure free IGF-I in a serum sample in vitro has been to obtain information about the bioactivity of IGF-I in target tissues, and thus relate a measurable parameter to biological responses such as longitudinal growth or glucose disappearance rate. In this review, the serum free IGF-I approach is placed into a physiological perspective. In addition, methodological aspects are discussed and suggestions for the validation of free IGF-I assays are presented.
Bang
P
P
Pediatric Endocrinology Unit, Department of Woman and Child Health, Karolinska Institute, Astrid Lindgren Children's Hospital, Stockholm, Sweden. peter.bang@kbh.ki.se
Ahlsén
M
M
Berg
U
U
Carlsson-Skwirut
C
C
D001774:Blood Chemical Analysis; D004704:Endocrinology / Q000379:methods; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D008433:Mathematics; D017551:Microdialysis
D007334:Insulin-Like Growth Factor I