Impact of Physiologically Relevant Genistein Exposure at Different Time Windows on Puberty Onset and Neuroendocrine Function in Female Rats

Scope: Puberty timing, critical for adulthood wellbeing, is influenced by the environment, life-style and diets. However, differential puberty-interfering effects of soy and soy isoflavone were observed in both epidemiological and toxicological studies. Additionally, their impact on neuroendocrine function at various pre-pubertal developmental windows is unclear.

Methods and results: This study investigated the effect of genistein, a typical soy isoflavone, at neonatal, lactational and post-weaning stages on the time of vaginal opening and determined the levels of neuroendocrine factors in female rats using immunofluorescence, immunochemistry, and enzyme-linked immunosorbent assays. A physiologically relevant dosage (10 mg/kg) was used to resemble human exposure. The results showed that genistein exposure at lactational stage significantly accelerated vaginal opening time, marginally increased hypothalamic gonadotropin-releasing hormone (GnRH) secretion, significantly enhanced Kisspeptin Receptor expression, and markedly elevated blood levels of GnRH, luteinizing hormone, and follicle-stimulating hormone, while neonatal and post-weaning exposures did not induce significant alternations.

Conclusion: Lactational stage might be an important window for genistein to impact reproductive development and neuroendocrine regulations. This article is protected by copyright. All rights reserved.