Estrogen Sensitivity and Ovulatory Dysfunction in Obesity

* Design: paired assessments Pre and Post estrogen administration in obese and normal weight women * AIM 1: To test the pituitary and hypothalamic responsiveness in obesity, we will examine the luteinizing hormone (LH) and follicle-stimulating hormone (FSH) pulsatility during frequent blood sampling. * AIM 2: To test the ovarian responsiveness in obesity, we will examine urinary reproductive hormones (E1c, estrone conjugates, and Pdg, pregnanediol glucuronide) over an entire menstrual cycle. * AIM 3: To test the hypothesis that central adiposity is associated with reproductive hormone alterations in obesity, we will quantitatively assess body composition by dual energy x-ray absorptiometry (DXA).