17β-Estradiol and testosterone amniotic concentrations in at term born puppies: preliminary results

The study of fetal sexual steroid hormones production during pregnancy deserve scientific interest in both humans and animals, to better understand the normal sexual development, but also in the recently investigated impact on the future health outcomes (Kuijper et al., 2013). Many studies reported the early production of testosterone by the testes during the fetal stage of development; however, also estrogens were recognized to play a role in developing programming. Because of the scarce knowledge about this topic in the dog, the present study was aimed to assess the 17-β-estradiol (E2) and testosterone (T) amniotic concentrations at birth in normal newborn dogs. The study was conducted on 31 normal puppies, 16 males and 15 females, born by 10 healthy bitches belonging to several breeds, submitted to elective Caesarean section at term, with litter-size ranging between 1 to 5. Amniotic fluid from each puppy was collected (Meloni et al, 2014) and immediately stored at – 20 ° C until analysis by RIA. Amniotic E2 concentrations in male and female puppies were 124±66.82 pg/ml and 109±42.15 pg/ml, respectively; while amniotic T concentrations were 124±91.24 pg/ml and 114±71.72 pg/ml, in males and females’ puppies, respectively, without significant differences between the two genders. The preliminary results showed that both E2 and T were detectable in canine amniotic fluid, but without differences between male and female puppies. The wide standard deviation found deserve further investigations on a larger number of subjects, to identify possible causes, such as the effect played by the bitch.