IGF uptake with competitive binding in articular cartilage

Abstract

Experiments on the transport of radiolabeled Insulin-like Growth Factors (IGF-I and -II) into bovine articular cartilage show differential uptake depending on the relative proportion of IGF-I and -II. In this study, we present a mathematical model describing both the transport and competition of IGF-I and -II for binding sites represented by two functional groupings of IGF binding proteins (IGFBPs). The first grouping has approximately similar binding affinity to both IGF-I and -II (i.e. IGFBPs 1-5), whereas the second group has significantly higher binding preference for IGF-II compared to IGF-I (i.e. IGFBP-6). Using nonlinear least squares, it is shown that the experimental equilibrium com..