Table 2.

Enzymes and Hormones Produced by Adipose Tissue

Enzyme/Hormone	Function	Changes Associated With Obesity
Aromatase	Converts androgens to estrogens	No change with obesity, but increased fat mass results in greater total conversion
17β-hydroxysteroid hydrogenase	Converts estrone to estradiol and androstendione to testosterone	No change
5α-reductase	Inactivates cortisol	No change
11β-hydroxysteroid dehydrogenase type 1	Converts cortisone to cortisol	Activity is increased in obese women
Leptin	Affects food intake, timing of puberty, bone development, and immune function	Circulating leptin levels are increased in obese women
Tumor necrosis factor α (TNFα)	Represses genes involved in the uptake and storage of nonesterfied fatty acids and glucose	Expression of TNFα is increased in the adipose tissue of obese women
Adiponectin	Enhances insulin action	Circulating levels of adiponectin are decreased in obese women