Sex hormone metabolism in upper and lower body obesity.

Morbid obesity has been previously shown to be associated with excessive production and metabolism of a variety of androgens and estrogens. Further, SHBG is lowered, resulting in high levels of 'free' testosterone. We have re-examined these parameters in morbidly obese women with upper vs lower body adipose distribution. Upper body obesity was associated with greater increases in production and clearance of testosterone and dihydrotestosterone compared to lower body obesity. Further, SHBG levels were lower resulting in high serum levels of free T and free E2 in this obesity phenotype. By contrast, lower body obesity was associated with increased peripheral aromatization of androstenedione resulting in higher urinary E1 production rates. The biologic significance of these hormonal differences in obesity phenotypes as well as the potential role of the androgen-estrogen environment in determining body fat distribution is considered.