Estradiol promotes and maintains the typical female phenotype characterized by subcutaneous fat accumulation. There is evidence to suggest that this effect relies on the ability of estradiol to increase the amount of anti-lipolytic α2A-adrenergic receptors, but whether this requires long-term exposure to estradiol or is the result of an immediate effect is not clear. Objective: To study acute effects of a single dose (4 mg) of 17β-estradiol on regional and systemic lipolysis.