Handling during pregnancy in the blue fox (Alopex lagopus): the influence on the fetal gonadal function.

In previous studies it has been shown that handling produced stress in pregnant blue fox vixens increasing plasma level and adrenal in vitro production of cortisol. Moreover, this treatment increased plasma cortisol levels in the fetuses. The present study was designed to examine effects of a 1-min daily handling stress applied to pregnant blue fox vixens on fetal gonadal steroidogenesis. Plasma concentrations of oestradiol and testosterone, gonadal content and gonadal in vitro production of these steroids, and response to exogenous hCG as well as gonadal weights, and anogenital distances were measured in control (C, n=69) and stressed (S, n=54) fetuses on 47-48 days of pregnancy. Maternal stress induced a suppression of gonadal steroidogenesis in the fetuses. The decreased testosterone content in the testes and oestradiol content in the ovaries were demonstrated in stressed fetuses compared with control (testosterone: 4.91+/-0.46 vs. 7.35+/-0.87 ng/both testes, P<0.05; oestradiol: 29.1+/-3.4 vs. 46.5+/-4.9 ng/both ovaries, P<0.05). The ovarian oestradiol in vitro production in female fetuses from stressed mothers was decreased in comparison with control (3.69+/-0.39 vs. 7.52+/-1.51 pg/ovary/h, P<0.05). The same difference was observed between stressed and control male fetuses in the testosterone testicular response to hCG (5.34+/-0.64 vs. 8.73+/-0.40 ng/testis/h, P<0.05). The ovarian weight from stressed fetuses was lower in comparison with control (12.9+/-0.7 vs. 16.8+/-0.6 mg, P<0.05). The anogenital distance in female fetuses from stressed vixens was also reduced (0.6+/-0.03 vs. 0.8+/-0.02 cm, P<0.01). These results indicate that prenatal stress resulted in a significant reduction of hormonal and morphometric measures of the reproductive system in blue fox fetuses with more drastic effects in female fetuses.