Endocrine Abstracts

The mechanism of the adverse influence of genistein; a soya phytoestrogen on foetal development is still poorly understood. Previous reports showed adverse effects on thyroid and leptin hormone, C-reactive protein and thyroxin kinase activities. This study evaluated the changes to the level of the insulin-like growth factor-I (IGF-1) and placenta growth factor (PGF) in rat pregnancy exposed to genistein. Pregnant rats grouped into 2 mg/kg and 4 mg/kg genistein treated groups were orally dosed daily with genistein dissolved in distilled water from gestational day (GD) one till sacrificed, while the control group received equal volume of distilled water. At GD-16 and GD-20, serum samples were collected and the placenta tissue carefully harvested and homogenized for the analysis of IGF-1 and PGF using ELISA method. Result showed that the serum level of PGF decreased at gestation day16 while it was increased at GD-20 in the 2 m/kg and 4 mg/kg groups. The placenta PGF level was significant increase in 2 mg and 4 mg/kg group at GD-16 while the level was significantly decreased in both 2 mg and 4 mg/kg at GD-20. Genistein at the two doses used, significantly reduced placenta level of IGF-I compared to control at GD-20 while it was only significantly reduced in 2 mg/kg at GD-16. Thus genistein alters these two growth factors and thus alters the normal growth and development of the placenta and the foetus especially towards term. The reported reduction in placenta and foetal weight in genistein exposed pregnancy is precipitated by the adverse effect on PGF and IGF-1 biosynthesis and proper growth-signal interactions with hormones and energy in the development of the placenta and the foetus.

Keywords: Genistein, Placenta, foetal growth, PGF, IGF-1, phytoestrogen, foetal programing