Genistein decreases androgen biosynthesis in rat Leydig cells by interference with luteinizing hormone-dependent signaling.

Testicular Leydig cells express estrogen receptors and are the predominant source of the male sex steroid hormone testosterone (T). Previous studies demonstrated that genistein acts through estrogen receptors in Leydig cells. In the present study, pre-treatment of Leydig cells isolated from 35 day-old male Long Evans rats with the epidermal growth factor receptor (EGFR) kinase inhibitor AG 1478 abrogated genistein inhibition of T biosynthesis.

Exposure to phytoestrogens in the perinatal period affects androgen secretion by testicular Leydig cells in the adult rat.

The use of soy-based products in the diet of infants has raised concerns regarding the reproductive toxicity of genistein and daidzein, the predominant isoflavones in soybeans with estrogenic activity. Time-bred Long-Evans dams were fed diets containing 0, 5, 50, 500, or 1000 ppm of soy isoflavones from gestational d 12 until weaning at d 21 postpartum. Male rats in all groups were fed soy-free diets from postnatal d 21 until 90 d of age.