Regulation of human villous trophoblast by insulin-like growth factors and insulin-like growth factor-binding protein-1

Many studies have implicated the insulin-like growth factors (IGFs) and insulin-like growth factor-binding protein-1 (IGFBP-1) in the control of the feto–maternal interface of human pregnancy, but many of the data are from cell lines derived from primary trophoblast or from extravillous trophoblast. We have obtained highly enriched villous cytotrophoblast (VCT) from first trimester and term human placentae, and investigated the effects of IGF-I, IGF-II and phosphoisoforms of IGFBP-1. First trimester villous trophoblast cells were regulated by all these factors. IGF-II increased cell numbers 3.5-fold after 96 h in culture, and IGF-I had less effect (1.5-fold increase) (both P