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ABSTRACT: Daidzein is one of the most important isoflavones present in soy and it is unique as it can be further metabolized to equol, a compound with greater estrogenic activity than other isoflavones. The potential role of daidzein in the prevention of some chronic diseases has drawn public attention and increased its consumption in human, including in pregnant women and adolescent. It is unclear whether perinatal exposure to daidzein through maternal diets affects subsequent behavior and central estrogen receptor α (ERα) expression in male adults. Following developmental exposure to daidzein through maternal diets during perinatal period, subsequent anxiety-like behavior, social behavior and spatial learning and memory of male mice at adulthood were assessed using a series of tests. The levels of central ER α expression were also examined using immunocytochemistry. Compared with the controls, adult male mice exposed to daidzein during the perinatal period showed significantly less exploration, higher levels of anxiety and aggression. They also displayed more social investigation for females and a tendency to improve spatial learning and memory. The mice with this early daidzein treatment demonstrated significantly higher levels of ERα expression in several brain regions such as the bed nucleus of the stria terminalis, medial preoptic, arcuate hypothalamic nucleus and central amygdaloid mucleus, but decreased it in the lateral septum. Our results indicated that perinatal exposure to daidzein enhanced masculinization on male behaviors which is assocciated with alterations in ERα expression levels led by perinatal daidzein exposure.
Progress in Neuro-Psychopharmacology and Biological Psychiatry 12/2012; · 3.25 Impact Factor
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ABSTRACT: The socially monogamous mandarin vole (Microtus mandarinus) shows significant behavioral plasticity. We examined whether levels of sociability, parental care and central expression of estrogen receptor alpha differed between two populations with different ecologies. Our results show that males from the Chengcun population display significantly more amicable and less aggressive behaviors towards novel same-sex individuals compared to males from the second population of Xinzheng. Chengcun voles directed more licking behavior towards neonatal pups than did Xinzheng voles. Differences were also found in the number of estrogen receptor alpha-immunoreactive neurons. For example, Xinzheng males displayed significantly higher immunoreactivity than Chengcun males in the medial amygdala, medial preoptic area and ventromedial nucleus of the hypothalamus. Xinzheng females expressed higher levels of estrogen receptor alpha-immunoreactivity than Chengcun females in the medial preoptic area. Chengcun females exhibited significantly more estrogen receptor alpha expression than Xinzheng females in the bed nucleus of the stria terminalis. Our results indicate that mandarin voles from the Chengcun site possess monogamous traits, and animals from Xinzheng possess polygamous traits. It also appears that different social behavior and levels of parental care in these two populations may be associated with differences in estrogen receptor alpha-immunoreactive neurons.
Journal of Comparative Physiology 03/2011; 197(3):267-77. · 2.01 Impact Factor
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ABSTRACT: Bisphenol A (BPA) is a widespread endocrine disrupting chemical that influences adult physiology and behavior after perinatal exposure. However, it is not clear if pubertal exposure to BPA exerts hormone dependent effects on behaviors. Using C57BL/6J mice, we sought to determine how pubertal exposure to BPA affects locomotion, exploration, anxiety and sociability in adulthood. Compared to controls, pubertal exposure to BPA or E(2) (17β-estradiol) significantly altered female exploratory and anxiety behavior. Moreover, BPA and E(2)-treated female mice displayed increased levels of affiliation to female stimulus mice and decreased levels of affiliation to male stimulus mice; while our control males showed affiliation preference to female stimulus. These results indicate that pubertal exposure to BPA or E(2) may masculinize female social and emotional behavior.
Environmental toxicology and pharmacology. 01/2011; 31(1):88-99.
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ABSTRACT: Various hypotheses have been proposed to explain factors influencing male alloparental behavior in cooperatively breeding species. Mandarin voles (Microtus mandarinus) are ideal animal models to investigate these factors because they are highly social rodents and display biparental care and spontaneous parental care when exposed to foster pups. Here we test the idea that the sexual and paternal experience of males influences alloparental behavior toward novel pups, and that these experiences alter the expression of neuropeptide oxytocin (OT) and estrogen receptor alpha (ERalpha). Alloparental behavior and OT and ERalpha expression were compared between virgin males that had no prior sexual or reproductive experience, exposed males that with prior exposure to novel pups before the test, paired males that had been housed with a female, and new fathers having their first litter with a female. Our results show that prior exposure to novel pups and prior mating and paternal experience increased male alloparental behavior toward a novel pup. This experience also increased OT expression and affected the expression of ERalpha. This study reveals important initiation factors for male alloparental behavior and suggests a relationship between alloparental behavior and central OT expression in males.
Behavioural brain research 12/2010; 214(2):290-300. · 3.22 Impact Factor
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ABSTRACT: Daidzein is an important isoflavone in soy. The potential role of daidzein in the prevention of chronic diseases is attracting growing scientific and public attention. This has led to an increase in the consumption of daidzein by humans, including adolescent and pregnant women. However, it remains unclear whether developmental exposure to daidzein affects behaviour and/or oestrogen receptor alpha (ERalpha) expression in adults. After dietary exposure to daidzein in mice during pregnancy and lactation, we observed behaviours in their female offspring during adulthood during open field, novel cage, elevated plus-maze, Morris water maze and social interaction tests. Central ERalpha expression was also examined using immunocytochemistry. Compared with a control group, female mice exposed to daidzein during early development through their mother showed significantly more affiliation behaviours when they encountered female stimuli. The acquisition and retrieval of spatial memory in the water maze test were also significantly improved by exposure to daidzein. Finally, females exposed to daidzein showed significantly less ERalpha expression in bed nucleus of the stria terminalis and medial amygdala. In combination, our findings show that maternal exposure to daidzein has a masculinisation effect on memory and social behaviour, suggesting a potential role of ERalpha distribution in the brains of female mice when regulating these behaviours.
Behavioural pharmacology 07/2010; 21(4):283-91. · 2.85 Impact Factor
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ABSTRACT: Various hypotheses have been proposed to explain factors influencing male alloparental behavior in cooperatively breeding species. Mandarin voles (Microtus mandarinus) are ideal animal models to investigate these factors because they are highly social rodents and display biparental care and spontaneous parental care when exposed to foster pups. Here we test the idea that the sexual and paternal experience of males influences alloparental behavior toward novel pups, and that these experiences alter the expression of neuropeptide oxytocin (OT) and estrogen receptor alpha (ERα). Alloparental behavior and OT and ERα expression were compared between virgin males that had no prior sexual or reproductive experience, exposed males that with prior exposure to novel pups before the test, paired males that had been housed with a female, and new fathers having their first litter with a female. Our results show that prior exposure to novel pups and prior mating and paternal experience increased male alloparental behavior toward a novel pup. This experience also increased OT expression and affected the expression of ERα. This study reveals important initiation factors for male alloparental behavior and suggests a relationship between alloparental behavior and central OT expression in males.
Behavioural Brain Research.
