Fetal testis and estrogenic endocrine disrupters

Estrogens play a major role in female reproduction, but there is now compelling evidence that
they may also be involved in the regulation of the male reproductive function. In humans, a decrease
in sperm count and an increase in the incidences of testicular cancer, cryptorchidism and
hypospadias, have been observed in many countries in the last fifty years. Changes in the male
reproductive function have also been observed in wildlife. These male reproductive disorders have been attributed to xenobiotics, and particularly to xenoestrogens, which have steadily increased
in diversity and concentration in the environment and in food. Epidemiological, clinical
and experimental studies have suggested that excessive exposure to estrogens and xenoestrogen
during fetal/neonatal life can lead to reproductive disorders in adulthood.We showed, in
an in vitro model, that estrogens directly affected the development of the fetal testis. We also
clearly demonstrated that fetal and neonatal testes were very sensitive to estrogens, as the invalidation
of the estrogen receptor alpha led to an increase in steroidogenesis, and the invalidation
of the estrogen receptor beta enhanced development of the germ cell lineage in the male.