INSULIN-LIKE GROWTH-FACTOR-I AND INSULIN-LIKE GROWTH FACTOR-BINDING PROTEIN-1 IN TAIWANESE WOMEN DURING NORMAL-PREGNANCY

Circulating levels of insulin-like growth factor-I (IGF-I) and insulin -like growth factor-binding protein-1 (IGFBP-1) in Taiwanese women dur ing normal pregnancy were investigated. Three hundred and eighty-five pregnant women at various gestational ages and 30 nonpregnant females were recruited into the study. Serum concentrations of IGF-I and IGFBP -1 were determined by immunoradiometric assay (IRMA) and radioimmunoas say (RTA). Maternal serum levels of IGF-I increased as pregnancy progr essed. Circulating IGF-I levels in women during the first trimester of pregnancy were higher than those in nonpregnant females. Serum levels of IGFBP-1 rose rapidly before 12 weeks of gestation and remained hig h until term. Serum IGFBP-1 levels in pregnant women during the first trimester were significantly higher than those in nonpregnant females. However, there was no difference in maternal serum IGFBP-1 levels bet ween the second and the third trimester of pregnancy. It is concluded that serum IGF-1 levels during pregnancy may be regulated by various c lasses of ICF-binding proteins other than IGFBP-1.