The effects of insulin-like growth factor-I (IGF-I) and IGF-II on prolactin (PRL) release from human decidua and amniotic fluid circulation

It has been reported that insulin-like growth factor (IGF) may play an important role in the feto-placental environment during pregnancy. The present study was undertaken to investigate the effect of IGF-I and IGF-II on prolactin (PRL) release from human decidual cells in vitro and in vivo. The human decidua in early pregnancy was obtained by D & C, and was enzymatically dispersed into a monocellular suspension. Monolayer cultures of these cells were exposed for 96 hours to either control media or medium supplemented with IGF-I and IGF-II. PRL levels in the media were measured by EIA. Five days after dispersion, the intracellular calcium concentration ( Ca]2+i) in cultured decidual cells was measured by the Fura-2 fluorescence method with a Spectrofluorometer. PRL and IGF-I levels in amniotic fluid of 2nd trimester and term pregnancy were measured by RIA for in vivo study. In an in vitro study, IGF-I increased PRL release from decidual cells significantly during a 96 hour culture. However, IGF-II did not enhance this PRL release. IGF-I stimulation had no effect on Ca]2+i. In an in vivo study, amniotic fluid IGF-I levels in the 2nd trimester (139.8 +/- 28.1 ng/ml) were significantly higher than those in term pregnancy (46.4 +/- 14.2 ng/ml), and a significant positive correlation (r = 0.852, p less than 0.001) was observed between IGF-I and PRL levels in the amniotic fluid. The present in vivo and in vitro studies indicated that IGF-I plays an important role in PRL release from decidua into amniotic fluid.(ABSTRACT TRUNCATED AT 250 WORDS)