Abstract :
In some species, including swine, cattle and sheep, the placenta synthesizes all the enzymes
needed to convert cholesterol into progestagen and estrogen. However, in goat reproduction
the processes specific to and the knowledge of goat placental steroidogenesis is
unclear. Therefore, the objective of the present study was to investigate the steroidogenic
pathways used by the goat placenta to synthesize androgens and estrogens, with special
emphasis on androgen production. Five postpartum placentas obtained immediately after
expulsion were processed for the study. A cell suspension was prepared from excised
cotyledons and aliquots incubated in DMEM and antibiotics, and 3H-progesterone, 3Hdehydroepiandrosterone,
3H-androstenedione or 3H-testosterone. Steroids were extracted
from the culture media and analyzed by thin layer chromatography (TLC). Testosterone and
androstendione were then recrystallized from the placenta incubation media. Placental
tissue was processed for in situ-RT-PCR in order to investigate the expression of 17 -
hydroxylase/17,20 lyase. Results showed the synthesis of tritiated androgens and estrogens
when cells were incubated with 3H-progesterone. The incubation with 3H-testosterone
or 3H-androstenedione yielded 3H-17 -oestradiol and 3H-oestrone. Placental cells also
transformed 3H-DHEA to the androgens 3H-androstenedione, 3H-androstenediol and 3Htestosterone
and also to 3H-estrogens. Androstendione and testosterone synthesis were
re-confirmed by recristallization. The results of this study show that goat placental cells
may use both the -4 and the -5 steroidogenic pathways to synthesize androgens and
estrogens. These data show the steroidogenic pathways used by the goat placenta to yield
androgens, and the ability of both androstendione and testosterone to be converted into
estrogens for the first time.
