Testosterone, a follicular regulator: key to anovulation

Area of Science:

• Reproductive Endocrinology
• Steroid Biochemistry

Background:

• Follicular steroid interrelationships are key to understanding dominant follicle selection and anovulation.
• The precise roles of specific steroids, like testosterone, in follicular development require further elucidation.

Purpose of the Study:

• To investigate the intricate relationships between various steroids within the ovarian follicle.
• To determine the influence of follicular steroid concentrations on enzymatic activities like 5 alpha-reductase and aromatase.

Main Methods:

• Combined 6-hour infusions of radiolabeled dehydroepiandrosterone sulfate and testosterone ([14C]T) in four women undergoing surgery.
• Measurement of multiple steroid concentrations in arterial blood, venous blood, and follicular fluid.
• Analysis of correlations between steroid product/precursor ratios and follicular steroid levels.

Main Results:

• A negative correlation was observed between the [3H]dihydrotestosterone/[3H]testosterone ratio and follicular estrone (E1) and estradiol (E2) concentrations, indicating a reciprocal relationship with 5 alpha-reductase.
• A significant positive correlation between follicular estradiol (E2) and testosterone (T) suggests a stimulatory effect of T on aromatase.
• Follicular testosterone (T) appears to enhance aromatase activity, particularly when follicle-stimulating hormone (FSH) levels are adequate.

Conclusions:

• Follicular testosterone acts as a regulator, boosting aromatase activity under sufficient FSH stimulation.
• These findings provide insights into the mechanisms of dominant follicle selection and follicular atresia.
• The study suggests a common pathway in the pathophysiology of anovulation related to follicular steroid dynamics.