The influence of psychological stress in early life on sexual maturation and sexual behavior in male and female rats.

Kiyohito Yano,Takako Tokui,Altankhuu Tungalagsuvd,Takeshi Iwasa,Kou Tamura,Yiliyasi Mayila,Rie Yanagihara,Minoru Irahara,Munkhsaihan Munkhzaya,Rie Masaki,Hidenori Aoki,Shuhei Kamada,Aki Hayashi,Toshiya Matsuzaki

doi:10.1002/rmb2.12313

Kiyohito Yano, Takako Tokui + Show 12 more

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https://doi.org/10.1002/rmb2.12313

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Abstract

PurposeWe studied the influence of psychological stress during the early neonatal period on sexual maturation and sexual behavior in rats.MethodsNeonatal male and female rats were divided into control (C) and maternal separation (MS) groups (n = 20‐24 per group). The pups in the MS groups were placed in isolation cages for 240 minutes/d from postnatal days 2‐11. Vaginal opening (VO) in females and preputial separation (PS) in males (indicators of sexual maturation) were monitored, as was the estrous cycle in females. Thereafter, sexual behavior was monitored twice at 13 and 15 weeks of age.ResultsAs for sexual maturation, the onset of PS occurred significantly earlier in the MS group than in the C group, whereas the onset of VO did not differ between the groups. The length of the estrous cycle did not differ between the groups. The frequencies of sexual behaviors did not differ between the groups in either sex.ConclusionsIn conclusion, early‐life psychological stress induced by MS advanced sexual maturation in male rats, whereas it did not affect sexual maturation in female rats. On the other hand, early‐life psychological stress might not affect sexual behavior in adulthood in either sex.

Highlights

It has been reported that several kinds of stress that occur during the perinatal period have a long-lasting influence on physiological and psychological functions
We have shown that neonatal psychological stress induced by maternal separation (MS) only advanced sexual maturation in male rats, resulting in elevated serum testosterone levels in the peripubertal period
We have shown that neonatal psychological stress did not affect sexual behavior in either sex, at least under the present conditions

Summary

| INTRODUCTION

It has been reported that several kinds of stress that occur during the perinatal period have a long-lasting influence on physiological and psychological functions. | 136 were lower than those of the children of normally nourished mothers.[4,5] in rats we have shown that sexual maturation was disturbed in both the male and female offspring of undernourished mothers.[6,7,8] These findings indicate that prenatal nutritional stress has adverse effects on physiological, psychological, and reproductive functions, and these changes might cause certain diseases in later life. It has been reported that immune stress in childhood increases the risk of cancer, lung disease, and arthritis/rheumatism and alters cardiovascular functions in later life in humans.[9] we have shown that neonatal immune stress increased appetite and body weight gain in male rats and disturbed the estrous cycle in female rats in adulthood.[6,10] In addition, Walker et al and we have shown that neonatal immune stress impaired sexual maturation and sexual behavior in male and female rats.[11,12] These findings suggest that perinatal immune stress, as well as nutritional stress, affects metabolic and reproductive functions in later life. In the present study we examined the influence of early-life psychological stress induced by MS on sexual maturation and sexual behavior in later life in both sexes

| MATERIALS AND METHODS

| DISCUSSION