Measurement of Insulin-Like Growth Factor Binding Protein-3 Proteolytic Activity with Western Immunoblot in Acute Viral Diseases in Childhood

Insulin-like growth factor binding protein-3 (IGFBP-3) is a main binding protein for IGF-I and II (IGFs). During pregnancy IGFBP-3 proteolytic activity has been found in sera and it may result in an increase in IGFs bioavailability so that the maternal tissues and placenta can grow. The proteolytic activity has also been reported to be induced in catabolic conditions such as after surgery and the subsequent increase in IGFs bioavailability may be important in overcoming catabolic conditions. We have this time established the measurement of the proteolytic activity using western immunoblot. This dose not use radioabeled IGFBP-3 and takes less time than the previous method. With the new method we measured the proteolytic activity in children with acute viral disease. Significant results of IGFBP-3 proteolytic activity were obtained from 2 patients with measles, suggesting IGF-I and II might also be physiologically important in those patients.