Effects of obesity on sex steroid metabolism.

In a study designed to compare plasma androgens in obese, anovulatory women with non-obese, ovulatory women, we found a statistically significant increase in plasma androstenedione and testosterone in obese, anovulatory women. Plasma androstenedione was 252 +/- 18 ng/dl (mean +/- SEM) in the obese women compared with 173 +/- 9 ng/dl in the non-obese ovulatory women (p less than 0.001). Plasma testosterone was 66 +/- 5.7 ng/dl (mean +/- SEM) in the obese women compared with 41 +/- 3.0 ng/dl in the non-obese ovulatory women (p less than 0.001). Androstenedione and testosterone are the substrates for estrone and estradiol-17 beta production. Menstrual disorders associated with obesity are largely due to estrogen excess. From the findings of this study we suggest that androgen excess in obesity results in subsequent tonic estrogen production and estrogen excess.