Study of the steroidogenic pathways involved in goat placental androgen and estrogen synthesis

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, 3H-dehydroepiandrosterone, 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 17α-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-17β-oestradiol and 3H-oestrone. Placental cells also transformed 3H-DHEA to the androgens 3H-androstenedione, 3H-androstenediol and 3H-testosterone 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 Δ-4 and the Δ-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.