Background: Daidzein is a major isoflavone in soybeans. Several in vivo studies have showed that daidzein can affect immature male testosterone production. However, whether daidzein has direct action on immature male testis is unknown.
Objective: We investigated the effects of daidzein on testosterone secretion in 3-day-old and 21-day-old mouse Leydig cells with organotypic culture model.
Materials and Methods: The testes were exposed to different concentrations (10-7 to 10-4 M) of daidzein for 72 h with medium changed every 24 h. From 72 to 75 h of culture, 100 ng/ml human chorionic gonadotropin (hCG) was added. The testosterone production was determined, and the related mechanisms of daidzein action were also evaluated by measuring the mRNA levels of steroidogenic acute regulatory protein (StAR), cholesterol side-chain cleavage enzyme (P450scc), and 3β-hydroxysteroid dehydrogenase (3β-HSD-1) involved in testosterone biosynthesis.
Results: The results revealed that in the presence of 100 ng/ml hCG, 10-7 to 10-5 M daidzein had no significant effect on testosterone secretion in cultured 3-day-old mouse testis. But 10-4 M daidzein significantly increased testosterone concentration (p < 0.05). Daidzein in range of studied doses had no obvious influence on testosterone production in cultured 21-day-old mouse testis. RT-PCR results showed that 10-4 M daidzein had obvious influence on the mRNA levels of StAR, P450scc and 3β-HSD-1 in cultured 3-day-old mouse testis (p < 0.05).
Conclusion: These results suggest that daidzein mainly influences neonatal mouse testis function, and the influence is partially related to the upregulation of StAR, P450scc, and 3β-HSD-1 mRNA levels.