Menopausal Hormones and Sympathetic Activation

The purpose of this study is to understand how changes in menopausal hormones like estradiol and follicle-stimulating hormone (FSH) impact sympathetic nervous system function. To do so, the investigators will use a medication to control the production of estradiol and FSH, and in some participants, add-back estradiol to isolate its effects. The investigators will measure sympathetic activation centrally (in the brain using MRI), peripherally in the nervous system, and also examine adrenergic receptor mediated control of vascular function.