Abstract
Insulin‐like growth factors (IGFs) play an important role in cell growth and differentiation, and the liver is the main source of IGFs and IGF‐binding proteins (IGFBPs) that appear in the circulation. The effect of liver cysts on the circulating IGF system was studied in this work. Serum concentrations of IGF‐I and ‐II were measured by radioimmunoassay, IGFBP patterns were characterised by ligand‐affinity and immunoblotting, and a lectin‐binding assay was used to investigate the glyco component of IGFBP‐3 complexes. IGF‐I and ‐II concentrations in patients with cysts were significantly lower compared to those in healthy individuals (P<0.0001 and P<0.01, respectively), and the decrease was related to age but not sex. The overall mean concentrations of IGF‐I and ‐II were not significantly different whether the cysts were caused by Echinococcus granulosus, cross‐reactive pathologies, or some other factor. IGFBP profiles correlated with the amount of IGF present: patients with lower IGF‐I concentrations expressed decreased IGFBP‐3 and elevated IGFBP‐2 levels. Increased IGFBP‐3 proteolytic activity in the patients' blood was not detected by immunoblotting. In the lectin‐binding assay, IGFBP‐3 complexes in the circulation of patients demonstrated reactivity similar to that in healthy persons, suggesting that the overall structure of the saccharide moieties of the IGFBP‐3 complexes was not significantly altered due to liver cyst formation. J. Clin. Lab. Anal. 18:299–304, 2004. © 2004 Wiley‐Liss, Inc.