Effect of genistein on the sexual maturation in immature female rats

Exposure to phytoestrogens in utero and age at menarche in a contemporary British cohort

“…Studies have found that phytoestrogens can cross the placental barrier in humans, and one study of Californian women undergoing amniocentesis found that 96% of second trimester amniotic fluid samples contained quantifiable amounts of dietary phytoestrogens (Foster et al, 2002). Additionally, as previously described, studies in rodents have found that exposure to high doses of isoflavones in utero and through diet in early life accelerated pubertal onset in female animals (Casanova et al, 1999; Takashima-Sasaki et al, 2006; Takagi et al, 2004; Kouki et al, 2003; Lewis et al, 2003; Bateman and Patisaul, 2008; Lee et al, 2009; Nagao et al, 2001). …”

“…In utero exposure to phytoestrogens are of particular interest because of the timing of differentiation and development (Casanova et al, 1999; Takashima-Sasaki et al, 2006; Takagi et al, 2004). Studies in rodents have found that isoflavones administered through diet or subcutaneous injection during gestation or early life can lead to early vaginal opening (akin to early menarche in humans), irregular estrous cyclicity, and decreased GnRH (gonadotropin-releasing hormone) activation (GnRH coordinates reproductive maturation and function) (Casanova et al, 1999; Takashima-Sasaki et al, 2006; Takagi et al, 2004; Kouki et al, 2003; Lewis et al, 2003; Bateman and Patisaul, 2008; Lee et al, 2009; Nagao et al, 2001). To date, few studies have examined the effects of lignan metabolites on pubertal development, particularly age at menarche (Kim and Park, 2012).…”

High serum isoflavone concentrations are associated with the risk of precocious puberty in Korean girls

“…Depending on the prevailing concentration of endogenous oestrogen, isoflavone may act as an agonist or a competitive antagonist 22 . In experimental studies, acute exposure to genistein during the prepubertal period resulted in the increase of ovary and uterus weight in young female rats 15 . Whilst exposure to a high dose genistein increased activity of ER β and reduced activity of ER α in uterus in young female rats 23 .…”

“…However, as these bioactive phytoestrogens possess a wide range of hormonal activities, it has been postulated that an adverse effect of isoflavones may be earlier onset of puberty 13,14 . Experimental animal study has shown that acute exposure to genistein during the prepubertal period resulted in earlier virginal opening and hypertrophy of luminal and glandular uterus 15 . However, the effects of isoflavones on pubertal maturation in human have not been investigated.…”

“…13,14 Experimental animal study has shown that acute exposure to genistein during the prepubertal period resulted in earlier virginal opening and hypertrophy of luminal and glandular uterus. 15 However, the effects of isoflavones on pubertal maturation in human have not been investigated. Studies on the hormonal effects of isoflavones are important among Koreans because their usual diets include high levels of isoflavones, from foods such as tofu, miso (soybean paste), soybeans, fried tofu and soymilk, compared to diets in Western countries.…”