Relationship between Insuline-like Growth Factor-I and Progesterone Secretion of Cultured Human Trophoblast Cells in Vitro

ObjectiveTo investigate the effect of insuline-like growth factor-I (IGF-I) on progesterone genesis and regulation.MethodsCytotrophoblast cells were collected by trypsin-collagenase digestion and percoll gradient centrifugation for primary culture. After stimulated with different concentrations(100 μg/ml, 10 μg/ml, 1 μg/ml, 0.1 μg/ml) of IGF-I at the same time and with different duration(12 h, 24 h, 48 h, 72 h) of IGF-I with the same concentration, progesterone levels in the media were measured by radioimmunoassay. Simultaneously, semiquantitative reverse transcriptase polymerase chain reaction(RT-PCR) was applied to determine the expression of low density lipoprotein receptor (LDLR) mRNA.ResultsProgesterone levels correlated positively with IGF-I along with the IGF-I concentration increasing, progesterone level began to increase at 12 h, and reached the climax at 48 h when cultured with 100 µg/L IGF-I. The expression of LDLR mRNA was detectable in every group and accordant with variation of progesterone level.ConclusionProgesterone secretion has time- and dose-dependent effect on IGF-I, and IGF-I can up-regulate the expression of LDLR mRNA. IGF-I may play an important role in promoting secretion of progesterone in trophoblast cells.