Elevated Production and Metabolic Clearance Rates of Androgens in Morbidly Obese Women

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Abstract
Blood production rates of testosterone, dihydrotestosterone (DHT), and 3α-androstanediol (3α-diol) were found to be approximately 2-fold elevated in morbidly obese, nonhirsute, normally menstruating women. Values were intermediate between those found in normal women and those in a group of nonobese normally menstruating women with idiopathic hirsutism. Elevated androgen production rates in obese women were associated with 2-to 3-fold increases in MCRs, presumably due to decreased levels of sex hormone-binding globulin. Thus, increased production rates were offset by increased MCRs, resulting in plasma testosterone, DHT, and 3α-diol concentrations that were similar in the obese and normal women. By contrast, women with hirsutism had increased production rates associated with elevated plasma androgens as well as increased MCRs. Urinary excretion of testosterone glucuronide and 3α-diol glucuronide (3α-diol G) were elevated in both obese and hirsute women, paralleling the increased androgen production rates. Despite increased production rates and excretion of androgens, obese women exhibited no menstrual abnormalities, hirsutism, or other signs of virilism. To explore the apparent ineffectiveness of increased androgen production to produce virilizing symptoms, we measured plasma 3α-diol G levels as a measure of peripheral androgen action. The mean ± SE plasma 3α-diol G was 53 ± 8 ng/dl in obese women and 36 ± 6 in normal women; by contrast, women with idiopathic hirsutism had levels of 440 ± 99, a 12-fold elevation. Plasma testosterone glucuronide in obese and hirsute women were only 2-to 3-fold elevated, while plasma DHT glucuronide was not increased in obese women and was only 2-fold elevated in hirsute women. Thus, obesity is a state of increased androgen production and accelerated clearance. 3α-diol G levels in obese women were only minimally elevated, in contrast to values in the hirsute women, perhaps reflecting the apparent androgeh ineffectiveness.