Insulin-like growth factor binding protein-1: identification, purification, and regulation in fetal and adult life.

Circulating IGF bioactivity is reduced under a variety of conditions where anabolism is impaired. Serum IGF binding activity is increased in acutely diabetic animals and is regulated according to insulin status. Alterations in serum IGF binding activity reflects, at least in part, changes in circulating levels of IGFBP-1, suggesting that IGFBP-1 is an important modulator of IGF availability in post-natal life.