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The role of testosterone in males has been extensively studied. However, studies in several species suggest that estrogens are also important for the development and function of male brain, bone, gonads as well as for spermatogenesis and sexual behavior. Data related to testicular P450-aromatase expression and estrogen receptors α and β in several species had been published. However, to our knowledge there is no information on testicular mRNA aromatase expression, estrogen synthesis, or estradiol-17β concentrations in the circulation of the male goat. Thus, the objective of this work was to conduct in vivo and in vitro studies related to estrogen synthesis and serum concentrations during the postnatal testicular development in goat bucks. To do this, circulating concentrations of estradiol-17β and testosterone were evaluated in male goat during the first year of life, starting at 15 days of age. Besides, in order to assess the estrogen-producing ability of testicles from prepubertal male goats (four months), testicular cells were incubated with tritiated androgen precursors ( 3 H-androstenedione and 3 H-testosterone) in the presence or absence of the P450-aromatase inhibitor formestane, using TLC to identify sex steroids. Finally, the expression and tissue distribution of P450-aromatase mRNA in the testis of 3–5 month old males was evaluated by in situ RT-PCR. Results indicate that estradiol-17β is present in the serum of male goats at 0.5 months of age, and that there are significant increases at 3 and 10 months of age. The in vitro synthesis of tritiated estradiol-17β was inhibited by the P450-aromatase inhibitor formestane. Messenger RNA for P450-aromatase was abundantly expressed both in Sertoli cells in the testis of goats of ages three, four and five months. The expression of P450 mRNA was also localized in Leydig cells. It is concluded that the prepubertal goat has measurable quantities of serum estradiol-17β and that their testis has the capacity to synthesize estrogens during this period.

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 3 H-progesterone, 3 H-dehydroepiandrosterone, 3 H-androstenedione or 3 H-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 3 H-progesterone. The incubation with 3 H-testosterone or 3 H-androstenedione yielded 3 H-17β-oestradiol and 3 H-oestrone. Placental cells also transformed 3 H-DHEA to the androgens 3 H-androstenedione, 3 H-androstenediol and 3 H-testosterone and also to 3 H-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.