Sex-specific prenatal stress effects on the rat reproductive axis and adrenal gland

Social stress during pregnancy has profound effects on offspring physiology. This study examined whether an ethologically relevant social stress during late pregnancy in rats alters the reproductive axis and adrenal gland structure in post-pubertal male and female offspring. Prenatally stressed (PNS) pregnant rats (n=9) were exposed to an unfamiliar lactating rat for 10 minutes/day from day 16-20 of pregnancy inclusive, while control pregnant rats (n=9) remained in their home cages. Gonads, adrenal glands and blood samples were obtained from 1 female and 1 male from each litter at 11-12 weeks of age. Anogenital distance was measured. There was no treatment effect on body, adrenal or gonad weight at 11-12 weeks. PNS did not affect the number of primordial, secondary or tertiary ovarian follicles, numbers of corpora lutea or ovarian FSH receptor expression. There was an indication that PNS females had more primary follicles and greater ovarian aromatase expression, compared to control females (both P=0.09). PNS males had longer anogentital distances (0.01±0.0 cm/g versus 0.008±0.00 cm/g; P=0.007) and higher plasma FSH concentrations (0.05 ng/ml versus 0.006 ng/ml; s.e.d. = 0.023; P=0.043) compared to control males. There were no treatment effects on the number of Sertoli cells or seminiferous tubules, seminiferous tubule area, plasma testosterone concentration or testis expression of aromatase, FSH receptor or androgen receptor. PNS did not affect adrenal size. These data suggest that the developing male reproductive axis is more sensitive to maternal stress and that PNS may enhance aspects of male reproductive development.