Androstenedione and testosterone biosynthesis by the adrenal cortex of the horse.

The research explores how the adrenal cortex of a horse produces androstenedione and testosterone using a homogenate from the horse’s adrenal cortex tissue and tritiated pregnenolone. The study concludes that the primary androgen produced by mare adrenals is androstenedione, which could influence the production of blood androgens in normal and hyperandrogenic horses.

Explanation of the Research

• The pivotal goal of this research is to scrutinize the biosynthesis of androstenedione and testosterone in the adrenal cortex of horses. The adrenal cortex refers to the outer portion of the adrenal gland, which is responsible for producing hormones that are vital for life, such as cortisol (which helps manage stress) and aldosterone (which controls blood pressure).
• For the purpose of this research, a tissue homogenate from the adrenal cortex of a mare was carefully extracted and subsequently incubated in the presence of tritiated pregnenolone. A tissue homogenate involves breaking down the tissue into a uniform mix that enables easier access to cells and their components while tritiated pregnenolone is a radioactively labelled type of pregnenolone, a precursor molecule that can be converted into either steroids or neurosteroids. This experiment design allows researchers to track the pathway for steroid hormone production.
• During this incubation process, the synthesized androstenedione and testosterone were extracted, purified, and co-crystallized to constant specific activity with the help of unlabeled carriers. The co-crystallization process aids in purifying the androstenedione and testosterone, enabling researchers to determine their concentrations accurately.
• The findings suggested that the rate of conversion of pregnenolone to androstenedione and testosterone was approximately 5% and 0.15% respectively, indicating that androstenedione was produced at a significantly higher rate than testosterone in the adrenal cortex of the mare.
• This result suggests that mare adrenals predominantly produce androstenedione. Given that androstenedione is a type of androgen, a group of hormones that play a key role in male traits and reproductive activity, it’s suggested that adrenals could play a significant role in the production of blood androgens in both normal and hyperandrogenic mares (mares with abnormally high levels of androgens).